How to install stock android on Huawei P9? As you may know, Huawei ships its devices with their very own Emotion UI. I recently received such a device and was shocked someone willingly destroyed such a great phone with such a bad UI. It especially hurt, since I was coming from a Nexus device.

Due how extensive the problems are, there is no remedy other than installing stock android. But, is it a working remedy? Am I able to find stock android installation, which supports fingerprints and double back camera?
willingly destroyed such a great phone with such a bad UI. It
  especially hurt, since I was coming from a Nexus device.
  
  Due to the above, there is no remedy other than installing stock
  android. But, is it a working remedy? Am I able to find stock android
  installation, which supports fingerprints and double back camera?


Your best hope is that some one creates a AOSP-ROM for your device. But looking in http://forum.xda-developers.com/p9 forums there is none. Since you say you came from nexus device I can only hope next time you make some  searches in XDA or get.cm where you can find most popular devices. For the moment P9 has some ROMs in xda but not as clean as AOSP.