After you get the gym badge from the Circhester Gym, you continue southeast to Route 9.
Explore the Route
Just to the left of where you exited Circhester, there is a sparkle. Check on it to get 3 Full Heals.
At the bridge at the start of the route, the pokémon that you can encounter by fishing are Octillery, Pyukumuku, and Wishiwashi.
West of the bridge, you can battle Fisher Harriet, who has a level 39 Barraskewda and a level 39 Lanturn. You get 2496 Pokédollars for winning.
Go southeast from there. The pokémon that you may see in this area are Gastrodon (East Sea), Jellicent, Mareanie, Pelipper, and Pyukumuku. The pokémon that can be found in rustling patches of grass are Cramorant, Kingler, Octillery, and Pincurchin.
North of the first patch of grass, there is a Max Potion.
Go south from there and you can battle Dancer Zoe, who has a level 39 Galarian Darumaka and a level 39 Bellossom. You get 2496 Pokédollars for winning.
South of that, you reach the Circhester Bay area of Route 9.
Circhester Bay
In Circhester Bay, the pokémon that you can encounter by fishing are Lapras, Mantine, Mantyke, Wailmer, and Wailord.
Go southeast and there will be a cutscene. If you're ready to proceed, say Yes when challenged to a battle.
The Team Yell Grunt has a level 39 Linoone and a level 40 Pangoro. You get 3200 Pokédollars for winning.
Afterward, your Rotom Bike is upgraded to be able to ride around on water as well as on land. This opens up some new areas. You can skip the next section if you just want to proceed with the story.
Explore New Areas with Rotom Bike
First, go west from where you first got the upgraded Rotom Bike, and ride the bike west across the water to find a Zoom Lens.
Then go north in Route 9 until you reach the bridge, and ride your bike northwest across the water. The pokémon that you may see in this area are Jellicent, Mantyke, Pelipper, and Qwilfish.
Go west in the water, and look for the southern path near the western bridge. Go down that path and you will find a level 55 Glalie. You can't catch it yet because of its high level, so you might want to avoid it for now.
Beyond the Glalie, you find TM64 Avalanche.
Get a TM in Galar Mine No. 2
If you go to Hulbury and go southeast into Galar Mine No. 2, you can go south in the mine until you find a narrow path to the east. Go that way, then ride your bike north across the ponds to find TM53 Mud Shot.
Visit New Parts of the Wild Area
If you go to Hammerlocke Hills in the Wild Area, you can ride your bike west and go across the water to reach the previously inaccessible Lake of Outrage area.
If you go to East Lake Axewell in the Wild Area, you can ride to the island in the middle of the central lake, to the area known as Axew's Eye.
Visit the Area West of the Professor's House
If you go to the Professor's House on Route 2, you can ride the Rotom Bike east from the bridge south of the Professor's House to find a Choice Band.
If you go west from that bridge, you can ride the Rotom Bike southwest to find a Psychic Seed.
If you keep going south along that waterway, you find a Water Stone.
If you go to the island in the middle of the lake, there is a sparkle. Check on it to get a Rare Candy.
North of that, behind some bushes, there is a PP Max.
If you go northwest from that island, you find a level 50 Obstagoon.
North of the Obstagoon, there is a sparkle on the left side. Check on it to get a Max Ether.
Continue north and follow the path to find TM69 Psycho Cut.
Moving On
When you're ready to proceed, ride your bike across the water in the southeast part of Circhester Bay in southern Route 9.
The pokémon that you can see in this area are Mantine, Mantyke, Remoraid, and Wailmer.
Go west in the water and there is a small cove to the northwest where you will find a sparkle. Check on it to get a Pearl.
Go south from there to find a Max Revive.
Keep going west and you can battle Black Belt Carter, who has a level 41 Grapploct. You get 2624 Pokédollars for winning.
Near the trainer, check on the sparkle to get a Black Belt.
South of that, if you go to the southwest corner of the beach, you find 3 Dive Balls.
East of that, talk to one of the swimmers to get TM45 Dive.
Go southeast from there, then go east in the water to reach some solid ground. There you can battle Black Belt Reece, who has a level 41 Sawk and a level 41 Throh. You get 2624 Pokédollars for winning.
North of that, you can visit Stephan's Pokémon Camp. Talk to Stephan to add this as a Flying Taxi destination.
West of the camp, go up the narrow path to find a sparkle. Check on it to get a Rare Candy.
Go south from the camp, then east. The pokémon that you may see in this area are are Barbaracle, Bergmite, Clobbopus, Dhelmise, Octillery, and Toxapex. The pokémon that can be found in rustling patches of grass are Cramorant, Gastrodon (East Sea), Inkay, and Pincurchin.
In the northwest corner of the patch of grass, check the sparkle to get a Never-Melt Ice.
East of the grass, you can battle Fisher Marina, who has a level 39 Qwilfish and a level 40 Pyukumuku. You get 2560 Pokédollars for winning.
Go southeast from there to where a Grapploct is going in a circle around a piece of ice. Go to the northeast of that area to find a Protector.
Go west from there and you can battle Swimmer Jacob, who has a level 39 Cloyster. You get 2496 Pokédollars for winning.
Go south and then west, and there is a cove to the north where you find a sparkle in front of a rock on the east side. Check on it to get a Normal Gem.
Go west and you can battle Swimmer Logan, who has a level 40 Wishiwashi and a level 40 Wailord. You get 2560 Pokédollars for winning.
Go west from there to find TM22 Rock Slide.
Then go all the way east to find a berry tree. If you keep shaking it, you can have a wild pokémon encounter with Greedent.
Near the berry tree, you can battle Swimmer Scarlett, who has a level 39 Remoraid, a level 40 Octillery, and a level 40 Mantine. You get 2560 Pokédollars for winning.
From there, go west, and then south. Check the sparkle on the beach to get a Pearl.
South of that, there is a sparkle in the middle of three rocks. Check on it to get a Max Elixir.
Check on the sparkle on the west side of the beach to get a Big Pearl.
Nearby, you can battle Swimmer Layla, who has a level 39 Toxapex. You get 2496 Pokédollars for winning.
Go south and you will reach the Outer Spikemuth area of Route 9.
Outer Spikemuth
The pokémon that you may see in this area are Bergmite, Clobbopus, Dhelmise, Jellicent, Mareanie, and Toxapex. The pokémon that can be found in rustling patches of grass are Liepard, Morpeko, Perrserker, and Thievul.
Go south through the grass and check on the item to the left to get a Scope Lens.
To the west, you can battle Music Crew Owen and Andrea, who have a level 41 Maractus and a level 41 Toxtricity. You get 5248 Pokédollars for winning.
To the north, if you keep shaking the berry tree, you can have a wild pokémon encounter with Greedent.
You can optionally go west into Hammerlocke. Otherwise, go east to where there are some storage crates. Check on the sparkle near the crates to get 3 Dire Hits.
Go east and there will be a cutscene. Afterward, go south through the grass, then go to the northwest corner of the fenced-in area to find a sparkle. Check on it to get 3 Guard Specs.
Before you go east to talk to Marnie, you can go west through the Route 9 Tunnel. There are no battles, items, or wild pokémon in the tunnel. When you have gone through the tunnel, you reach the east side of Route 7, which was previously blocked by Team Yell.
Route 7 East
Go west and you can battle Gentleman Caden, who has a level 44 Doublade, a level 44 Passimian, and a level 44 Polteageist. You get 8800 Pokédollars for winning.
Northeast of the gentleman, you find TM58 Assurance up against the railing.
Nearby, you will find Renee's Pokémon Camp. This adds the camp as a Flying Taxi destination.
If you go south from there, then east, you find a ramp just south of the bridge that leads to an area with a pair of Safety Goggles on the east side and a berry tree on the west side. If you keep shaking the berry tree, you can have a wild pokémon encounter with Greedent.
From there, you can go west to Hammerlocke to heal up, then go back to Route 9 and challenge Marnie.
Battle Marnie
Marnie has a level 42 Liepard, a level 43 Toxicroak, a level 44 Morpeko, and a level 43 Scrafty. You get 5280 Pokédollars for winning.
Afterward, head north into Spikemuth.