SP's: iOS 9 SDK includes new APIs and services that are enabling new categories of apps and features. Multitasking and gaming APIs help enhance app functionality and create immersive games. Expanded search capabilities, and new support for CloudKit, HomeKit, HealthKit, and MapKit extend iOS to more places than ever before.
In a Apple announced tons of new features and hardware including, , Watch OS2,, 3D touch etc. All these are which apple is going to release on 16th Sep and soon iOS 9 powered devices will be in the hands of hundreds of millions of customers around the world. iOS 9 SDK is available for developers to build and convert apps for iOS 9 and get it reviewed by Apple.