Opponent loose-passive. hasn't been too aggressive.

Is this standard or just terrible??

I'd raise 2x-2.5x pre...otherwise, std.

Your assessment of the player says it all- Loose/Passive, meaning he sees a lot of flops(any two) and plays passively when he has missed, so he could easily have two pair here. However this is a relatively dry board and with AJ you are also beating every Jack that hasn't two-paired. I personally would've jammed him on the flop and lost

2x pre, 450/c otf.

if he has reads that his opponent is very loose from the bb, 3x pre is perfectly fine (and preferable actually). otherwise raise smaller yeah.

postflop: against any other player than a loose passive one i would always just float his raise otf and play it like u did since he should be pretty polarized and have a fair share of bluffs, against a loose passive one im not really sure what to do though. if he is the type to raise and overplay any top pair for value then i would probably raise it back otf and try to gii and avoid any scary turns or rivers that might kill the action, otherwise idk, i guess we cant fold TPTK on such a dry board even if he is super passive, so your line is fine.

I guess i was hoping to get max value out of KJ. The way he was playing i put him on KJ and thought a spewyish shove would get good value. Didn't put him on 2 pair.

ur call on the flop was ok, the call on the turn obv terrible :x
even if u would beat him with this call 50% of times there (but i guess u wont beat a loose passive player in this spot after this play more than 20% of the time)
it would be bad because ur chance to win this game just by waiting for better
spots is so high vs this kind of fish