Kim HAS nuclear bombs, and he HAS ICBMs. It is not clear, yet, that Kim has the ability to insert the bombs on top of the missiles and reliably detonate them on a target half the earth away. He certainly could attain that capability, left alone to develop it. Trump has no choice but to act now.
Right now, Kim wouldn't dare to unleash his unproven technology on a power with proven missile defenses. With Trump's bold actions, he likely never will.
Kim’s nuclear capabilities and development got much reduced when his mountain fell down.