Gotta be Cool, Cat

I've seen a few stories similar to this one in premise, where a cat becomes a humanoid in order better "serve" their masters or caretakers. A Cat Repaying Kindness in Kazoku Donburi by Mitarashi Kousei is a fantastic one and the the most like this, and others like Cat-Head Imako and Ootsuka Kotora's Lespedeza play off of it by the girls pretending to be the human embodiments of cats.

The Cat Returns (Original) [Itou Yuji]
E-Hentai
DDL