You are right exit, he might have KQs or KJs and making a check raise here.

Honestly, I think if he did have that, it would be a bad place to make a check raise, just for the slight chance hero might have ace something and take a free card at an ace. I really hate to check raise myself, I think it is often misused, and can get you in trouble more often than it can help you, and so many people use it as pure bluffs now, that I don't even see it as a powerful play. It does make me analyse the situation though whenever it happens to ask myself what he might have. Not saying the check raise is bad all the time, it does have some good places to use it, I am just saying that it is often not done in good spots, or used as it should, as a way to extract more chips from someone who wouldn't have called if you bet.

But back to the issue, I think the only possible holdings I could think of limping then calling your raise pf from a decent player would be (and most of these, I would never limp with UTG):

AKo, AKs, KQs, KQo (maybe), KJs, 99, JJ (maybe making a play at the pot), and POSSIBLY 22 depending how loose his calling standards are. Every now and then though, I see someone making a strange limp/call from UTG that makes me scratch my head. I played a sng earlier today, and 2 different people limped with queens pf then called my raise, then called down with a K on the flop. I had 10's and J's both times, and didn't put either one on that hand.

Regardless on whether you think you are behind or not on this hand, pot odds are looking good, and only hand that you are really behind I think is 99, so its likely that the hand is still best. Good call there.