It seems that on an iPad running iOS 9, UIImagePickerController is totally broken when allowsEditing is set. No matter how you crop and scale the photo, only the top left part of it is returned in the imagePickerController:didFinishPickingMediaWithInfo: delegate for the image corresponding to the UIImagePickerControllerEditedImage key.
I filed rdar://22856685. Aside from writing my own crop & scale UI, does anyone know of a workaround?