Agree that you are reaping either 8/9 or your own over pair here. Just don't know how believable either really is. If you have you own over pair, it probably isn't tens or better, right? Otherwise, why flat from SB? Maybe Ts is the wrong break, but it isn't a super premium pair to my read. So, if he has even a semi-decent pair, will probably call.
Could be 8/9, but what are the chances of that really? You called from SB and 8/9 has gotta be near the bottom of that range, no? I suppose your range from the SB might be infinity if you are trying to protect against what you read as a steal from the button, but there are only six combos of 8/9 in the deck so ...
Further, you also rep the flush draw (which you actually have) and that failed. If I am him, and you jam the river, I would see that I am getting roughly 4:3 odds
. So, if it's even 50/50 that you do not have 8/9, probably worth a call. Given that the flush draw line of semi-bluff raise to c-bet bluff on the turn is definitely a substantial part of the range as played, it's gotta be at least 50/50 that you do not have 8/9
disclaimer: Only been playing this game for 9 months, so I probably have more to gain from responses to this post than you have from my ideas themselves.