Notes: UTG is a bad player that likes to get aggressive in wrong spots and makes light calls.
BTN plays too many hands and is passive pf. He opens fairly wide from the BUT if folded to him which makes me believe he has at least some positional awareness. He hasn't yet shown aggression in a spot where he didn't had a good hand.

Never played with any of them before so my reads are limited.

Microgaming - €0.10 PL Hi (6 max) - Omaha Hi - 5 players

UTG: €7.54
CO: €14.05
BTN: €9.20
SB: €8.22
Hero (BB): €15.35

SB posts SB €0.05, Hero posts BB €0.10

Pre Flop: (pot: €0.15) Hero has 8 5 9 6

UTG raises to €0.20, fold, BTN calls €0.20, fold, Hero calls €0.10

Flop: (€0.65, 3 players) 8 6 7
Hero checks, UTG bets €0.30, BTN raises to €1.10, Hero ??

What do we do here? I don't think BUT is being funny here with a set or 2p+draw. I think he always has a straight here. I'm not sure if he'd do this with 59 or only 9T. He would prob raise the lead from the fish with 59, but would he do it with us behind? Should we ever raise here? If by chance he has clubs we're drawing very slim. Plus we still have another player behind that donked at the flop.

Hero calls €1.10, fold

Turn: (€3.15, 2 players) 5
Hero checks, BTN bets €2.90, ??,

Just shove flop and turn. With so much equity and possibly the best hand there's just no way we can exit at any point.

wow have a doublegutterstraightflush draw? is that even the correct term?
i think i would just fold flop. i dont think UTG has nothing when stabbing this you had him behind to act. So either 9T is out there or some of your boat outs are dead FD is coverd... you are slightly behind vs 9Txx and way behind vs 9T+fd.

Never folding this for less than 100bb

Gii vs the flop raise
But you can probably just lead flop

I'd just fold flop. I'd definitely fold turn as 45 isn't potting, so we're beaten or chopping with what might be a freeroll on the fd side and 4 outs to a boat.