Considering Close Situations

Usually, people spend the most time talking about hands where the situation is very close. I think this situation is a close one, but I'd appreciate comments if people think I'm overlooking something.

This is in 6 handed $200 maximum buy in $1/$2 NL HE game online. The button is a new player, having just posted his first blind this round. I sat down a few orbits before and I have only a little over $200. The button has $197, and raises to $7 when the action folds to him.

I called $7 in the SB with 9 9, and the big blind folded. The pot stands at $16 with a flop of 2 3 5.

I bet out $9 into $16, figuring for a fold if he has overcards and a raise if he has an overpair. I'm not going all the way with this hand if he raises; I'll give him credit for TT or something and fold. He just calls. I figure he's capable of doing this with just overcards with an ace for a gutshot. He also could be slow-playing a monster, but I didn't get the sense he could have an overpair, because unless it's aces, he can't really let a card come off.

The turn is the 9 and I led $15 into $34. My hope is that now he continues to call if he just has overcards, and perhaps decides to pounce now if he does have aces or some such. Again he just calls.

At this point, I admit to being confused about his holding. He could have flopped a set, which he continues to slowplay. A4 is possibility, but it seems strange he'd slowplay that now with a two flush on board.

The river is the Q. I led $50 into $64. At this point, if he has AQ and has been ripping with overcards and a gutshot, I figure he'll just call. I was a bit surprised when he moved all-in for $116 more. I didn't really think he'd slow-played QQ all the way down, and that was about as likely as a pure bluff with a missed straight draw — probably together they make up 5% of the time at most and cancel each other out. I decide that he either has A4, or one of the flopped sets, and decide to call, getting nearly 1-to-1.5. He actually held the stone cold, 46o.

It seems to me that I just have to get stacked here, and I'm not terribly unhappy about the play. But, I've been running badly enough that I am in that mood of questioning these sorts of situations and wanting to be really sure I didn't screw up.

I thought a bit about betting less on the river, which would have made it much easier to fold to an all-in. But I felt that there were some hands that would pay off that amount, and given that I didn't know anything about the player, he could easily have misplayed aces or a flopped set.

The other post mortem thought I had was to bet much more on the turn, something an overbet of around $40. The problem is, he might still just call with a flopped set, so the overbet doesn't actually tell me whether he has a flopped straight or not.

Did I royally screw up here, and if so, how should have I played it to lose less? Is this really a close situation, or did I just totally miss the obvious?