I think all options are viable. Just cant imagine many flushes in his range unless he defends preflop all low suited connectors. But on the other hand, is he actually valuebetting a K? Because he doesnt have many of them which wants to bet the turn. I see only K9s. That said, I think his river bet is polarized to a flush and really few combos of Kx. That said, raising doesnt seem that great to me, so the question is if calling>folding?

On one hand I see that our range is well protected by Kx and he lacks unpaired bluffs.. however, we have got premium Ah blocker which leaves him with so few value combos.. that he needs to be turning really few amount of PPs into a bluff in order to have a +ev call with our hand.
That said, even though they underbluff, I think its not enough to make this exploitative fold, due to the low amount of value combos.