Your son had his top teeth removed a few years ago and they still havent come through yet and he is 8 is this normal?

This is PERFECTLY NORMAL. He may be a late-bloomer tooth-wise, but at 8 years old many children's adult teeth have not grown in. If I remember correctly, my adult front teeth grew in when I was around 7-8 years old, while some children my age lost theirs at 10! It can also depend on genetics, compare his tooth growth to your own or another family member's.