My late cat Squeak used to play. MOST cats do some jumping on the keys, but Squeak actually sounded surprisingly good, probably due to a combination of stepping gently and having paws precisely a perfect 4th apart.
My uncle once saw me in the hallway, and was confused because he heard the piano playing in the apartment. "Who that?" he said. "The cat," I said. "The cat? I thought you were trying something atonal!" I got into the happen of hitting the tape recorder whenever she would get on the keys, just to have a record of it.
When she got old and sickly and could no longer jump, she once stood and the foot of the piano and meowed, clearly asking to be picked up and place on the keys. And I did. And she walked on the keys and played. For the last time. What a wonderful cat she was.
I think you should record your cat playing and maybe make a whole composition based around what she does, called "Chin Music." He sounds adorable.
As for other composers, I think Jerry Lee Lewis has done something similar.