I wouldn't call an UTG 5x bb raise with KJo to play it for 1 pair.

If you want to call the flop bet and chase your kicker, that's your option and the odds are against you. Check the turn and fold the river.

As far as putting someone on a hand, unless the player is a LAG, he won't raise less than AQ UTG. And he's not likely to bluff the flop missed in this case.
Range of hands for your opponent on this hand based on his betting pattern and position are AA, KK, AK, QQ (small chance of this).