Walkthrough
With the Circhester Gym conquered and Hop defeated once more, you will proceed south of Circhester on Route 9. This long, watery path full of Wild Pokemon and Trainers that will lead you straight to Spikemuth, where the next Pokemon Gym can be found. There are three different sections to Route 9, but most of it is covered by Circhester Bay. You'll need to use your Rotom Bike in order to traverse the waters. You will also run into Team Yell on Route 9.
Main Area - Overworld:
Pelipper (40%): Levels 41-44
Mareanie(Sword)/Jellicent(Shield) (35%): Levels 41-44
Gastrodon (15%): Levels 41-44
Jellicent(Sword)/Mareanie(Shield) (5%): Levels 41-44
Myukumuku (5%): Levels 41-44
Main Area - Grasses:
Cramorant (40%): Levels 38-42
Octillery (30%): Levels 38-42
Kingler (25%): Levels 38-42
Pincurchin (5%): Levels 38-42
Main Area - Special Overworld:
Glalie: Level 55
Main Area - Fishing:
Octillery (60%): Levels 38-42
Wishiwashi (30%): Levels 38-42
Pyukumuku (10%): Levels 38-42
Main Area - Waters:
Pelipper (40%): Levels 39-43
Qwilfish (30%): Levels 39-43
Mantyke (25%): Levels 39-43
Pincurchin (5%): Levels 39-43
Circhester Bay - Overworld:
Clobbopus (30%): Levels 39-43
Octillery (24%): Levels 39-43
Toxapex(Sword)/Barbarcle(Shield) (20%): Levels 39-43
Bergmite(Shield) (20%): Levels 39-43
Bergmite(Sword) (15%): Levels 39-43
Barbarcle(Sword) (10%): Levels 39-43
Toxapex(Shield) (5%): Levels 39-43
Dhelmise (1%): Levels 39-43
Circhester Bay - Grasses:
Cramorant (40%): Levels 39-43
Gastrodon (30%): Levels 39-43
Inkay (25%): Levels 39-43
Pincurchin (5%): Levels 39-43
Circhester Bay - Special Overworld:
Grapploct: Level 50
Circhester Bay - Berry Trees:
Greedent (100%): Levels 39-43
Circhester Bay - Fishing:
Mantyke (50%): Levels 38-42
Wailmer (34%): Levels 38-42
Mantine (10%): Levels 38-42
Wailord (5%): Levels 38-42
Lapras (1%): Levels 38-42
Circhester Bay - Waters:
Wailmer (40%): Levels 39-43
Mantyke (35%): Levels 39-43
Remoraid (15%): Levels 39-43
Mantine (10%): Levels 39-43
Bergmite (40%): Levels 40-44
Clobbopus (30%): Levels 40-44
Mareanie (24%): Levels 40-44
Toxapex (5%): Levels 40-44
Dhelmise (1%): Levels 40-44
Perrserker (40%): Levels 40-44
Thievul (30%): Levels 40-44
Liepard (25%): Levels 40-44
Morpeko (5%): Levels 40-44
Outer Spikemuth - Berry Trees:
Greedent (100%): Levels 40-44
Trainers
Fisher Harriet: Level 39 Barraskewda, Level 39 Lanturn
Dancer Zoe: Level 39 Darumaka, Level 39 Bellossom
Team Yell Grunt: Level 39 Galarian Linoone, Level 40 Pangoro
Fisher Marina: Level 39 Qwilfish, Level 40 Pyukumuku
Swimmer Jacob: Level 39 Cloyster
Swimmer Logan: Level 40 Wishiwashi, Level 40 Wailord
Black Belt Carter: Level 41 Grapploct
Swimmer Scarlett: Level 39 Remoraid, Level 40 Octillery, Level 40 Mantine
Swimmer Layla: Level 39 Toxapex
Black Belt Reece: Level 41 Sawk, Level 41 Throh
Musician Owen: Level 41 Toxtricity
Dancer Andrea: Level 41 Maractus
Items
Max Potion: Near Grasses In Northern Route 9
PP Up: Hidden In Southeastern Main Area
TM64: Northwestern Main Area
TM45: Northeastern Main Area
Rotom Water Bike: Defeat Team Yell
Zoom Lens: Northwestern Circhester Bay
Dive Balls: On Beach In Western Circhester Bay
Black Belt: On Beach In Western Circhester Bay
TM22: On Beach In Southwestern Circhester Bay
Max Revive: On Middle Island In Circhester Bay
Protector: On Southeastern Island In Circhester Bay
Max Elixir: On Beach In Southern Circhester Bay
Big Pearl: On beach In Southern Circhester Bay
Big Pearl: Hidden In Northeastern Circhester Bay
Pearl String: Hidden In Southern Circhester Bay
Wiki Berries: Berry Tree In Circhester Bay
Aguav Berries: Berry Tree In Circhester Bay
Iapapa Berries: Berry Tree In Circhester Bay
Petaya Berries: Berry Tree In Circhester Bay
Apicot Berries: Berry Tree In Circhester Bay
Scope Lens: In Fenced Area Outside Spikemuth
Dire Hits: Hidden In Front Of Crates By Spikemuth
Guard Specs: Hidden Near Boxes By Spikemuth
Lum Berries: Berry Tree By Spikemuth
Roseli Berries: Berry Tree By Spikemuth
Chople Berries: Berry Tree By Spikemuth
Tanga Berries: Berry Tree By Spikemuth
Salac Berries: Berry Tree By Spikemuth