Games like 9 Years of Shadows
Games like 9 Years of Shadows include Rabi-Ribi, Momodora: Moonlit Farewell, Hollow Knight, Ori and the Will of the Wisps, and Touhou Luna Nights. We matched them by the tags players give 9 Years of Shadows on Steam (Metroidvania, Platformer, Side Scroller, Fantasy, and Anime): closest matches first, and among equally close ones the better-known games.

Rabi-Ribi
Shared: Metroidvania · Anime · Pixel Graphics

Momodora: Moonlit Farewell
Shared: Metroidvania · Anime · Pixel Graphics

Hollow Knight
Shared: Metroidvania · Platformer · Exploration

Ori and the Will of the Wisps
Shared: Metroidvania · Platformer · Action

Touhou Luna Nights
Shared: Metroidvania · Side Scroller · Platformer

Bloodstained: Ritual of the Night
Shared: Metroidvania · Side Scroller · Anime

Skul: The Hero Slayer
Shared: Pixel Graphics · Platformer · Metroidvania

Afterimage
Shared: Metroidvania · Side Scroller · Anime

TEVI
Shared: Metroidvania · Anime · Pixel Graphics

Momodora: Reverie Under The Moonlight
Shared: Metroidvania · Side Scroller · Pixel Graphics

Hollow Knight: Silksong
Shared: Metroidvania · Platformer · Exploration

Dust: An Elysian Tail
Shared: Platformer · Metroidvania · Action

Blasphemous 2
Shared: Metroidvania · Fantasy · Side Scroller

Record of Lodoss War-Deedlit in Wonder Labyrinth-
Shared: Metroidvania · Platformer · Pixel Graphics

Rogue Legacy
Shared: Platformer · Metroidvania · Action

Dead Cells
Shared: Metroidvania · Pixel Graphics · Adventure

Owlboy
Shared: Platformer · Metroidvania · Pixel Graphics

Monster Boy and the Cursed Kingdom
Shared: Metroidvania · Platformer · Side Scroller

Bloodstained: Curse of the Moon
Shared: Platformer · Metroidvania · Pixel Graphics

BlazBlue Entropy Effect
Shared: Platformer · Action-Adventure · Pixel Graphics

ANIMAL WELL
Shared: Metroidvania · Platformer · Pixel Graphics

Iconoclasts
Shared: Metroidvania · Pixel Graphics · Platformer

Axiom Verge
Shared: Metroidvania · Platformer · Pixel Graphics

ICEY
Shared: Side Scroller · Anime · Action