$Freeroll NLHE MTT: River decision

Hi all.

I was just faced with a tough decision on the river in the CC freeroll.
I was playing on phone, so no stats.

Hero (UTG +1) is dealt KhTh

Villain (UTG) limps
Hero raises To 90 (30=BB)
Villain calls

Pot = 215
Flop Kd9d8s

Villain checks
Hero bets 90
Villain calls

Pot = 395
Turn 5h

Villain checks
Hero bets 180
villain calls

Pot =755
River 3h

Villain checks
Hero bets 420
villain shoves allin 2700.

Hero folds after thinking: why did he limp preflop, and checkcalled me every turn. did he have 76 of diamonds? AA? KK? I don't get it. Maybe I should have called his bluff? This doesnt make much sense.

Maybe Robcubus, if you see this, can enlighten me.

Bet larger preflop/flop/turn.

As played I'm calling here, villain almost never has a value hand here. K9/88/98/99 all raise at some point during the hand and it's unlikely K8 limps in pre. Villain x/shoving rather than raising non-allin looks very weak too.

I'm snap calling on this river