"Hey Siri" support and possibly wireless charging case alongside AirPower charging mat.
AirPods and AirPower: Everything We Know
Hidden Features in iOS 9 and OS X El Capitan
Apple's introduced a wide range of feature additions and minor tweaks in iOS 9 that make some very useful improvements to iOS. For example, there's now a Notification Center widget that displays the battery life of connected devices like the Apple Watch, and there's a search bar in the Settings app that lets you find a specific setting very quickly.
A "Back to App" feature lets you swap between apps quickly when you click a notification or a link, and some keyboard changes on the iPad make editing documents a whole lot easier.
OS X 10.11 El Capitan has fewer small feature additions, but there are some improvements worth pointing out. The famous rainbow wheel pointer or "beachball," which spins when a program is loading has brighter, more defined colors, and the cursor is now easier to find when waking a Mac from sleep. There's also a revamped Disk Utility window and a dedicated Find My Friends widget for the Notification Center.
If you want to see an overview of all of the features in the new operating systems, make sure to check out our roundups: iOS 9 and OS X 10.11 El Capitan. Our dedicated iOS 9 and El Capitan forums are also an excellent resource for learning more about the software we'll all be using in the fall.