We already made available to you the official wallpaper of OS X 10.11 El Capitan, but we still lacked the iOS 9.
Well here it is:

You can download the original image by clicking here. It is 2712 × 2706 pixels and weighs 12.1MB, so it can be used on both iPads and iPhones / iPods touch.
For now, both OS X 10.11 and iOS 9 s came with a new wallpaper each.
(via iPhone Hacks)