Like many have said in the thread, I've been running Windows 10 since it launched (upgraded from Windows 7) and I've never had any issues running the game. As a matter of fact, I've seen a slight increase in FPS in directX 11 but that could be the newer display drivers at play, not Windows 10 specifically.

As for official support, I'm pretty sure Square Enix doesn't officially support it just yet but you should have no trouble running the game. I wouldn't be surprised if they officially start supporting it come Patch 3.1