Root with this guide http://nvidiashieldzone.com/shield-android-tv/android-7-nougat/tutorial-root-shield-android-tv-2017-16gb-nougat/ it was a little difficult as it was my first time rooting an android product.
I then disabled the leanback launcher and and replaced it with an app called XBMC Launcher https://play.google.com/store/apps/details?id=se.blunden.xbmclauncher&hl=en . Now everything works great you can press the home button and bam right to SPMC. You can turn off the device, reboot, sleep, and it will still launch SPMC. GL!
PS make sure you read the prep and have all the required items.
If only kodi/sbmc didn't have such ugly UIs.