iOS 9.0.1 has gone live for the new iPhone 6s and 6s Plus. Users who receive their new iPhones can immediately get the update which will bring them on the same version number as rest of the iOS 9 compatible devices.
iOS 9.0.1 contains some minor fixes for Safari, ‘slide to upgrade’ bug and others so it is important that users update their phones at the first instance to avoid facing any of these issues. The complete change log for the update can be seen here.
Apple is also working on iOS 9.1 which has new emojis and performance improvements. The new updates should roll out along with the release of iPad Pro next month.