Im in the BB in the UB PLO Rebuy. We're early , blinds still 30/60. I have a stack of over 8K.

I get a free look at the flop with 8c8d9cJh

Flop comes 678 two hearts. SB Checks I bet the pot, all fold to SB who calls, this guy has show a tendency to call all in's with bottom set etc. The trun brings an offsuit ten, giving me the nut straight and a set. SB Checks I bet the pot. The river brings the third heart and SB Bets all in 1730 into a pot of 4320.

I folded but is there any way I should have made this call without a flush?

That's a tough river, the old 7-outer when you've got the nuts going two ways . Still, that's omaha. Because you have BOTH the nut set and the straight, and he's played passively throughout, I think you can put him on the flush draw a large percentage of the time and thus folding ain't too bad. The one slight concern is that he's bluffing a scare card, and only a half pot bet is perhaps callable if you think he might've been playing along with a lower set than you, looking to catch the boat. If the call crippled your stack i'd say definitely not, though here the answer is perhaps just about "maybe", but for me I think that's a fold most of the time in a tourney where preserving your decent stack without taking any marginal propositions seems like a sensible idea.

If the field was large I would've been tempted not to bet out on the flop, as you'll have to fold to a raise and, if there's one bet (or when bet and a call) after you check, you would have decent implied odds to continue with your 10-outer.