To be honest, I'd say A-9 was a more feasible option than 9-9.
I'd raise the flop and consider calling (and praying) on the Turn, although a lot of players do just shovel it in with the made hand too.
Good call though.
Not if he puts you on a set/two pair etc..
I don't know the answer to this as I don't play online multis, but do many players who believe their opponent has a set or two pair push hoping they'll fold?