If you think there's some Ax on his range, you can try a small bluf about $4,25 to simulate a thin value bet without a 7. It has to work only 28% of time.
If you think that he thinks 7 is in your range a bit often and he doesn't like too much to make calls in danger, you can try a big one about $8,50 or $9... this one should work almost half of the time.

Otherwise it would be a check behind, but I really like the first option I gave because he won't have an overpair more than 72% of time in my opinion. It's only 3 combos, as you said.

I would give up on the flop - as you said, his range consists mostfly of strong Ahi/mid pairs, and none of those fold on the flop, I assume. Also, we have almost no good turns to barrel with our hand, so it becomes a no-equity multibarrel vs UTG, whose range is super narrow -if he opens 15% and folds 75% - you seriously expect him to fold anything from the range his left with to 1 barrel? :D

I think a lot of players fold even AKo OTF in villain's shoes.
I'd bet a bit larger though.

I think 3bet pre is a bit iffy. OK to polarise when he is FT3B of 75%, but he is UTG and is likely to be pretty strong and therefore won't fold 75% of the time.
Plus I don't like flop cbet, yes it is dry but if you are cbetting here then you are cbetting most of your range and have no checking range. Your hand has virtually no equity here.

Although I expect the cbet to work quite often given he has likely missed the flop and is sitting there with overcards, I think I just check back and give up as we have no way to hit any meaningful draws OTT and villain is likely to peel with pocket pairs once.

OTR, I just give up, most of your strong hands, you would have bet OTR.

This is about the worst hand you could pick from all your possible hands to cbet with. You already have ace-high but don't have two overs or a bdfd. That said it isn't completely unreasonable to have a high cbetting strategy here (some obvious counterstrategies, like villain calling AA/KK and x/r'ing or x/c'ing flop, are quite unlikely to happen). After cbetting flop turn is one of the best cards for our range in my opinion as our bluffing hands tend to be more centered on 6-9 sort of stuff than villain's calling range, so I would continue betting.

I don't hate jamming river sometimes, you have more 7's than villain although neither of you has many. This isn't a terrible hand to jam with because you block AA and don't block any bdfds or hands like TT which are most likely to fold. I don't think bluffing a size less than all-in is going to make much sense because I think our hands which would want to bet that size probably just bet the turn.

I think with my 3bet sizing and the fact that he is quite q tight player, giving up seems most reasonable to me. If I c-bet then I agree with JoINrbs I should continue betting this runout.

Thanks for the replies :)

Agree with giving up otf

I think his range is heavily towards Pocket Pair hands and Ahigh card hands raising UTG with 15% RFI and the way he played the hand.
I don't think he would ever fold whatever you bet on the flop with the board texture.
The turn bet may put some consideration into his hand if he were to have like JJ-KK which he may be able to fold on the river if you triple barrelled him

So basically IMO I think after you gave up on the turn the pot is nearly unwinnable for a big percentage of his range
You may be able to get rid of A high cards hands by betting on the river after he checks to you.

I believe he would bet on the turn with any 7 or 77's so it's profitable to raise the turn then try and raise the river on most rivers.