IN September, not at or on. "At" would be
where to find the stable release: at September's place.
But get real: announced IN September but because of <some part in short supply- just make up any old part: the flaquomaster X7>, it will be in very short supply for up to forever. So wake up at 2:58am to try to be FIRST... or you may never, ever, never-ever, ever, never, never, never get one... nor your children, nor their children. Hurry! Rush! Apple might squeeze 5 or maybe just 10 units out of the factory before the next, next iPhone is announced.
However, by the prime of the holiday buying period, magical innovations in the supply chain yet again will manage to make it possible to get 1+ (or millions) in time for everyone to get one for Christmas. We fall for it every single year. It works every single year. We never seem to learn. See everyone at 2:58am.