KTo BB

It's a simple check on the Turn. It's too likely that one of your opponent has got the straight by the Q on the Turn and since nobody did raise the Flop so it makes Ax more unlikely and a hand like A2 A3 might fold on the Turn. There is not much merrit in betting but you should check the TUrn and see what happens. As played you had to call the Turn due to your outs. That makes the bet even worse. IF you could just b/f, i 'd rather agree to the play but you will rarely get out 2 more BB's out of many worse hand but it's more likely to be raised by a straight and lose more. If you'd have AK, it'll be better to keep betting since you beat some more worse 2pairs but you almost got the worst 2pair.

As you say Its check/Call Turn & Check/Fold River 3way
How about Heads up against a limper/ Preflop raiser OOP on this board?
Should I Check/Call both Turn& River?

Lets say you have a blindwar-situation, i'd recommend c/c Turn as well. The reason is that you just get value out of a few Ax hands that didnt reraise Preflop and hands like QT but on the other side he's got a lot of gutshots Jx and Qx on such a board and normally you should not expect to get value 2 streets from a hand like Q9 and neither a hand that is even worse like T9 or something but if you check, he may (bluff)bet or you'll get at least one more BB on the River but by betting the turn you don't lose much value from hands that would otherwise call down for 2BB. It depends on the limit. If you know he is a callingstation and calls down any pair, just go ahead and get your value from all his pairs but assumed he's kinda reasonable.