[FiSheYe]

Uh this is a tough spot without a read.
I mean we can come up with ranges and scenarios for thin calls or clear folds.
I mean it's obvious he is not doing this with a hand like TT+ neither do I see a hand like AJ here all too often.
Your hand could very well be an Overpair or better so why would he call the flop and make a move on the turn?
Imho there aren't many combodraws that he would call on the flop and then semi bluff on the turn.
On the other hand I don't see him here with 66 or 88 calling on the flop all too often either..
Kinda hard to figure out what he could have.
J9s makes sense, 57s, 99 (88, 66) maybe some sort of midpair call that turned into a combodraw...
To be honest when I cannot come up with a correct decision to either call or fold I doubt it makes a big difference.
Imho if he is loose agressive against you, there is a special history/background or he is steaming I would call.
If he is rather tight postflop and you haven't perceived him as one doing weird flop floats or reckless turn bluffs/overplaying his hands, he perceives you as nitty and not able to fold 2pairs (insert Villain read) then I tend to fold.
The interesting question is, against somebody you don't have a read on (first orbit, new site, agressive 10/20 play), what is the optimal line there?
Don't think you can do much wrong by either calling or folding.

Really interested to see what the good regs say.