Don't raise K9s preflop in this spot, you don't get value out of it, your are oop, and it is not like you want to fold the BB out trying to protect your hand.

c/ring should be done against a preflop aggressor who isn't Hero. Most of the time in shorthand the preflop aggressor will continuation bet the turn, so long as they are not super passive postflop.

A check raise is used when your hand is likely better than the pfr and you want to add value to your hand or protect your hand by charging the players behind you 2 to call.

True