Joining them would be Japan as well, and all of the three countries mentioned happen to be tier one Apple launch countries where iPhones are concerned, which would mean they will be made available at the same time that the device is revealed over in the US.
9to5Mac also claims that they have figured out that Best Buy has partnered with Apple in order to offer customers AppleCare protection plans from this coming September 14th onward, and this would then provide the company with a few days of run in time right before the iPhone 6S rolls out officially. Are you waiting impatiently to see what the iPhone 6S can do when it arrives?