I let him out. I finished the top overhangs on the deck fence, but looks like they're not needed. And this ended up being another breakthrough. Tonite he's acting very tame. He's letting me pet him, and he flipped on his back a few times and played with my fingers like a real kitten!
This is as far outside as he got before running back inside. I dumped the chair over just in case he panicked so he couldn't use it to jump off of. I think he MIGHT be able to make the roof if he really wanted to.