My thinking would be that its a pretty safe bet that he is not holding a set, maybe a set of nines but still doubtful. He should raise from the BB if he had TT or JJ to protect his hand from overcards on the flop fitting into the limpers hands.

I also do not think he has KQ (may have raised pre-flop also) since he would have nothing to fear with the nut straight and would not be interested in scaring you away since your pot sized bet indicated that the flop helped you and you may be willing to commit more money to this pot. That leaves either J10 in which case he is afraid of a straight draw busting him, or 87 in which case he would be afraid of a higher straight busting him.

If you think he has any of these hands, you cannot call. You only have four outs, one of which may already be in his hand, and you are not getting the pot odds to call a four-outer.

I would lay this hand down for two reasons. For me, in tournaments, I like to get all my money in when I have a bit more confidence that I can win. Here, you are really gambling that he is shoving all in with a complete bluff or an open ended straight draw. Secondly, of all the hands I discussed, he is most likely to have 87. He is not afraid to get all him money in because he has a made hand, but he really would like you to go away. The ass end of a straight is always hard to play as more cards out. He thinking is probably "I probably have a winning hand, but this guy is showing strength and I don't want to run into any more difficult decisions on fourth and fifth streets, so I'm just moving all in.

Lay the hand down. There is no embarrasment in laying down two pair on a board so well connected. As Doyle, says, there is no reason to go broke in an unraised pot(before the flop)!!!