CO 30/24 over 119 hands
cbet: 5/9

Had a little history with the CO in that I was winning a lot of small pots from him. He was opening his BTN ridiculously wide and I was 3betting him three times over a relatively short period of time and he always folded. I also won two or three small pots where just one bet went in postflop, either as PFA or defender and we played one 3handed pot where I c/c a set over two streets on a low rainbow board vs his 2street overcard bluff.
So I was basically expecting him to play back at some point because I was running ridiculously aggressive at his tables and winning a lot of small pots w/o SD from him and a bunch of other players.

BB 31/6 over 62 hands

Thought about raising here because I think I wanna have a wider (semi)bluffing range, especially because of the other player behind, and thus also raise my sets. However he seems like a thinking and aggressive player in general so I felt like this might a good spot to just flat at least topset. Because it's not that vulnerable on this board, it blocks a lot of his possible continuing range and because my flatting range looks very weak and I expect him to barrel a lot. I also don't think I lose that much value from overpairs on most runouts if I just flat.
And he might also back into TP with AQ which is obviously a huge win for me.

I knew this would be a tough spot if he went for a c/r but don't think this justifies checking back. However I wasn't entirely sure about how to continue facing his c/r. My 99 become a bluffcatcher now and I really didn't expect him to do this as a bluff all that often. Just because of our history I was expecting him to try leveling me into herocalling lighter than going for a sick bluff line.

Is this as played ok if I fold the river? Since I expect him to follow through there almost always I at least thought a bit about folding the turn but felt like he might sometimes giveup with AK one diamond on the river and I also have huge implieds on a boat I guess.