You could use two fingers on the home screen and draw them apart. This will bring up the hidden apps list (which may be empty) with a '+' at the top. Tap the plus, a list of your apps will appear and any you want to hide can be hidden this way, but not un-installed.
I own a P9 and I wanted to know ( found nothing on Google ) if there is any way to hide the software buttons ( a build in solution in the software ) or if they will integrate it in android N when it comes out for us.