I think this is "reverse results oriented". In other words, usually, players are results oriented about bad beats, but you are being results oriented about a hand where you got really lucky and got away with Fancy Play Syndrome.

This is fricking 2NL. 2NL is completely beatable by just putting in raises and c-betting flops. Maybe not this hand-- maybe your line worked better. But in general, fancy play can get you into trouble.

You waited for the turn here, which means you gave your villain a free card with which to hit some hand that he could beat your unimproved A9 with. And since one of the biggest leaks among low-stakes NL players is calling down their mediocre hands, you put the villain in a position where he could hit a mediocre hand and then call you down and take the pot.

I would strongly recommend that, at lower limits, you work on a strategy of ABC tight-aggressive poker. It may not be that exciting, and you may not be making a lot of brilliant, imaginative plays, but it happens to be a strategy that makes lots of money at low limits when correctly executed. Save these sorts of plays for when you get to a level where your villains are aware of how to play back at ABC players.