1. 99+, AQs+. More likely pocket pair like QQ or KK.
2. He reps Ak/AQ, KK/QQ and AA. Looks mostly like a big pocket pair that is not going to give up control of the hand when the Ace hits for fear of getting bluffed, or he hit the Ace after his C-bet.
3. Your range should be 8s, boats, Ax.
4. Hard to answer (profitably part). You are calling with something, and there are no draws for you to be calling with. He has to put you on Ax, 8s, boats, pocket pairs and bluffs (floating with the intention of repping the 8). He has a good hand, so there is a reasonable chance he is calling, though probably not often enough. Completely villain dependent and dependent on his view of your image.
5. Shove any 8, boat, AK.