My first response:
(If you don't have reads on people)
5 people saw the flop. That is a lot. Someone could easily have a better hand on that flop. 9T flops a straight and there wasn't much preflop action that would push the hand out. 56 made a straight on the turn and could call the flop. I doubt they are both calling along on flush draws. And mid and low pair isn't much to call on unless they have a inside straight draw too or something like that.

I say you only have top pair and a good kicker. AJ could have made a raise preflop but didn't necessary have to 10 handed. You would think they would put a bet on the flop but maybe they are just passive.

I say your hand isn't strong enough to build a large pot. I would say check and try to keep the pot small and give them a free card to their flush or possible inside straight draws. But it is somewhat dependent on your reads of your opponents. If they always call along you might reconsider.

edit: also lots of medium cards tend to see the flop cheaply and those could make two pair.