He's already posted pictures of him dunking on his Instagram. He walked around most of the year, post ACL, with no crutches. Rule of thumb is 9-12 months, but 6 is not uncommon these days, they're getting so good at this surgery and some peoples legs just distribute pressure a little differently and allow for easier healing. Hell, there's a few athletes with no ACLs at all.
Judging by his dunking and walking, and his general world class athlete status, I'd hope he'd be on the quick side of the estimated recovery.
(Aside: if you've ever seen Poy in person, he's truly a frightening athlete. Dude is a monster. If he doesn't get signed, he could be in under armour commercials. Hopefully this is the year the skills catch up with the insane physical gifts he was given!)