They bomb Hawaii, and the Japanese would turn NK into a smoking crater within a day.
The US wouldn't have to lift a finger.
I'm pretty sure we don't have to worry about a payload on this particular missile. They are just trying to see if they can launch a missile that will successfully separate, start its second stage, and continue on course. The biggest problem right now is...where's the booster going to land? Japan has already said it better not land there, or they'll consider it a hostile act.