Yes, they are old enough to be separated from their mom, though 10 to 12 weeks is ideal. Do you give them wet food as well? They need it in their diet in addition to kitten chow.
Please be careful when giving your kittens away that you know the people and their address and phone number and that they have yours. You want to make sure they are going to forever homes and will be spayed or neutered and properly loved and cared for. Please tell them to return the kitten to you if for any reason it does not work out.