The sites points to November availability.
So I was digging around the API diffs for iOS 9, now that it is updated with APIs to support new hardware features.
I was specifically looking into new APIs in UIKit to handle view controller previews and popping to full screen.
I noticed that all these APIs pointed to iOS 9.0 for availability.
But then I found new methods inside UITouch, specifically
preciseLocationInView - which pointed to iOS 9.1 for availability.
I thought that was a mistake.
But looking further into the new methods, for example
azimuthAngleInView where the return value is described as:
"The azimuth angle of the stylus, in radians."
...it clearly was no mistake, and these new API methods are for the Apple Pencil.