Sometimes on your way down when putting a kitty back on the floor they get scared and scratch.
My Mulder (kitten) has got me in the nose, my back (that one was bad) and she uses her claws a lot but I don't think is an aggression problem I can tell when it's been really aggression and many times in cats rough playing can be misinterpreted as aggressive behavior. Have you tried playing with him using a ball? Like a squash ball or a golf ball, throw it around your place and he can seek. I have done it with adult cats and they do respond to playing time in a lot of cases. Or with the light reflected by a mirror or a laser pointer, it could help maybe to give him some ease.
Maybe like SCM said and Chico it could be love bites