My 9 week old kitten just fell from the top of my stairs?

He seems fine physically, and he's playing now a little, he seemed really scared and shooken up from the fall when he hit the ground :( I didn't see it happen, I just heard a "thud" and came to see what happened and he was curled up on all fours. As I said he seems okay just a little scared now I guess. :( He is my first cat so I'm not too experienced with cats. Will he/is he okay? Should I be concerned? It was a long drop, if I fell from that height I WOULD break a bone probably. This happened like, 10 - 15 minutes ago. What should I do :( Help!