Update: Apple has also released the public beta of this build.
Mac Rumors has done a great job at recapping all the new features in the betas so far:
iOS 9.1 also includes Unicode 8, adding support for emoji like the taco, burrito, cheese wedge, middle finger, unicorn head, and more, plus it includes a new “Hey Siri” Settings feature that lets the “Hey Siri” command be customized for an individual user’s voice. On-demand voice activation even when not plugged into a power source using the “Hey Siri” command is a new feature in the iPhone 6s and the iPhone 6s Plus.
As was discovered in iOS 9.1 beta 2, iOS 9.1 also adds a new Messages option in the Settings app, allowing users to disable photos for their contacts.
And while they were at it, Apple also released iOS 9.0.2, the second minor update to iOS 9, to the public.
This update contains bug fixes and improvements including:
– Fixes an issue with the setting to turn on or off app cellular data usage
– Resolves an issue that prevented iMessage activation for some users
– Resolves an issue where an iCloud backup could be interrupted after starting a manual backup
– Fixes an issue where the screen could incorrectly rotate when receiving notifications
– Improves the stability of Podcasts