Lets assume the only two hands he can have here are 22 and A2, as both of those hands make the most sense. There are 3 combinations of 22 that he can still have, and 6 combinations of A2 remaining that he can have, making it still 2 to 1 that you're the huge favorite assuming that he does have a monster. Also, although the limp with a big ace would be a bit strange, its still possible (especially being the first limp), and is still WAY more likely than 99 or AA. Good aggressive players practically never open limp 99.

So ... your goal should be extracting chips here. My normal play would probably be call, expect him to bet any turn very hard and then go all in (where he's much more commited than he is now), but all in on the flop is fine as well (especially if you're putting him on A2 or 22 here and are sure he'd call with BOTH - he may be able to get away from A2 if he's really good and respects your play at all ... but probably not).

If you went all in and he called with 22 and won and you think you maybe played your hand badly, I'll be a bit disappointed that I wasted my time on this. Online tournament with rather fast blinds and not super deep stacks and you just have to go with this flop every time. If you're beat, it clearly was a very unlucky and rare flop.