Both players are regs w/ decent aggro styles.
Should I call, raise or fold the flop?

Call, other things are bad.

we've got enough equity to continue so folding is not an option. we still need to make our hand and all our outs are to the nuts so there is no reason to knock utg out.

It's probably mathematically very close whether it's better to raise or call assuming CO can raise and fold blockers. Best case scenario is that both villains have the nut straight, and in that case you want the money in on the flop (50% eq 3 ways). The mistake you make when you shove and push UTG out with his top two or bottom set is minimal, and could be offset by the times you win without a showdown, although its possible UTG would have been pushed out regardless.

You probably have an average equity of 40% 3 ways and 50% 2 ways. Obviously we would rather take the 40% 3 ways every time if we could, but this doesn't account for the times when both players fold. In the long run, this spot won't matter too much, as neither choice will likely be -ev.

I'd be interested if someone could do the math, and figure out how likely it is UTG folds a made hand AND CO was blocker bluffing.

I agree that anything but clicking call is likely bad

Can someone explain to me why raising is bad? We would shove the nuts here right? So this is a nice hand to balance

If we knock UTG out when he has something like two pair and a gutter, this is better for us. He will likely fold some hands that share outs with us, and we aren't worried about our equity against one other person in general. We could be dominated, but I assume if everyone here thinks a call is best on the flop, you would also continue when someone pots the turn unless the board pairs.

This is somewhat close to a pure math spot. Pure verbal reasoning is just guesswork. You should look at the spot more quantitatively (equity figures above are off, so I'm assuming you haven't, or that you've assigned bad ranges).

This is a rough estimate of the 3 way action, and obviously both players should be capable of b/f and r/f. Let me know what you think needs to be changed here.

ProPokerTools Omaha Hi Simulation

600,000 trials (Randomized)

board: t96

Hand	Pot equity	Wins	Ties
78xx,kqjx, qjt9, ttxx,99xx,66xx,qj8!7, t9xx	30.76%	144,178	80,799
78xx	31.74%	164,022	52,911
jhkdqs7h	37.51%	208,121	33,921