Eye Friendly Screen Options
Using the iPhone or iPad before you go to bed can wreck your sleep, and there are many reasons you shouldn't use the iPhone in bed. Even though we know it's a bad idea, it is really hard to stop using the iPhone or iPad at night since for many of us it is our newspaper, magazine, book, TV and alarm clock.
Official support for an app like f.lux would be an amazing option for iOS 9. Simply put displays don't mix well with sleep, but, "f.lux fixes this: it makes the color of your computer's display adapt to the time of day, warm at night and like sunlight during the day."
There are jailbreak tweaks to use f.lux on the iPhone and it is a great experience, but it would be even better if iOS 9 added support for this app and feature, even if it is bundled into iPhone Accessibility options.