He had just sat down 3 hands ago and I took him to be the typical calldown-> fold unimproved on the river fish, but I got the fold part wrong

I thought I could take down the pot vs T9,T8 weird Q and K highs etc.
I Agree the river bet is a bit too much given the dryness of the flop maybe if it was two toned then betting a blank river again would be better.
Now that I know I can't push him off 9 high (not even the nut 9 high) I wouldn't bet the turn or river.