I am playing too tight in this situation?

Hello,

This is my first post and I just recently started playing poker again. I am lacking in experience and I am still pretty bad at poker tbh, although I do know how to play ABC for the most part.

I recently started playing live 1/3 again and I just started playing 2nl on ACR.

I appreciate your advice!

Info about the villain:

We are playing 2nl on ACR
I have 200BB in my stack and Villain has a little over 100BB
My HUD has tracked 387 hands on the villain.
Villain has a VPIP of 20 and PFR of 12.
Villain folds to 3 bets 60% of the time.
Villain has an aggression factor of 1.9
From what I have observed, the villain seems to be playing in a pretty straight forward way.

Villain opens for 3bb with VPIP of 12% of hands from the HJ in a 6 max online cash game 2nl. Hero has KhKs in the CO, and Hero 3 bets to 9bb.

Villain calls. Flop comes 9h7d6s.

Villain checks and hero C bets 3/4 pot (14.5BB). Villain check raises me 38.5BB. Hero calls.

The turn is Jd.

Hero checks and villain bets ½ pot.

After making the bet, villain had 31BB left in his stack.

I fold thinking he has a set. Although I considered the possibility that he may be semi bluffing with hands like 88, TT, or a Ax of diamonds. I also consider the possibility that the villain may be overplaying a hand like J9s. However, I thought this might be unlikely.

In my previous session I lost a big pot with KK in a very similar situation to the one described above. I have no doubt that that painful memory likely influenced my decision here.