why does my black 9month old kitten do the things he does?!

He's an aggressive little kitten, that why. Some kittens just act that way, and if you want to change it, use a plant duster, with plain water in it, and then spray him when he does something you don't like.
One of my friends got his cat to stop stealing food, using that method, and he got it from his veterinarian.

Because he's a kitten. That's what they do. He will calm down eventually.

I have a black cat that does the same thing! When I walk out of the room he will charge after me and bite me on the leg! He can be very affectionate and loving when he wants to but he can also be very agressive. That's why I nicknamed him "The Prince of DaHKness!" :)

I had a cat just like the one you described. He was an out of control kitten and turned out to be ferocious towards anyone who possibly posed a threat to me. He even tried to kill a boyfriend of mine once. Is your cat an american shorthair? That's what my cat was and my mom has the same type of cat. Based on observation, this breed seems particularly aggressive. They are very loving too.

When they play too rough it should be discouraged.

Do it like an adult cat does...snarl and hiss..while pushing the kitten away. Then ignore him for a while. In this manner you will teach him what "too rough" is.

Best he should learn this now before he is fully grown and seriously able to hurt you because, contrary to the myth, not all kittens outgrow this behavior.

Cats (and kittens) are strange, but I love them anyway! Who knows why?