Don't worry about the air pressure found molded onto the sidewall of a tire, that is only its maximum allowable air pressure for use when the tire is carrying its maximum rated weight. So since your tires are only carrying maybe half of that max weight, the proper air pressure would be about half of whatever that air pressure on the sidewall would be, if you could see it.
30-33 psi is fine for your Jeep. 30 psi if it's fairly unloaded, a slightly higher psi like 33-34 if the Jeep is fully loaded with passengers, gear, etc..
When you have a choice, buy American.