[TOMT][video game] Wii game about a boy in a post-apocalyptic world who encounters souls

The game was in an anime style and released around 2008-09. It was about a boy in a post-apocalyptic world where he was by himself after his grandpa died. He left his home and started encountering harmless souls that, I think, he had to free. Eventually, he came across a girl with white/silver hair who pretty much just wore a white rag for clothing. I recall my favorite part being in a theme park, and he finds another boy who's kind of like a Scarecrow.