I'm not sure when their different teeth come in, but in the video --
your cat was play-biting a lot and you were encouraging it by grabbing
his paws. Don't use your hand as a toy with him! You're actually
teaching him that it's okay to bite.

At 8 weeks old he's old enough to be off of kitten milk. Try mixing
water in with it. Start with a little water then more each day until
eventually it's just water.

Good luck,

Rhonda