I think this depends on how loose passive your opponent is here. Will he call K-x or a busted straight draw on the river, how many straight draws will he have played?

There are quite a large amount of A-x that he would call down and some 9-x which he will raise. I don't think that you beat enough hands to bet/fold. I think check/fold is probably better. Since he is passive we don't expect him to bluff bet the river on a missed draw?

True