[Pi 4]

Easy answer for you - if all you need is Kodi - then LibreELEC Kodi Krypton is one of the best Kodi releases going around. It will handle a lot more content seamlessly compared to Android Kodi. There is now an Army of AMLogic S905(x) devices that can run LibreELEC Kodi.

Personally I would not even mess with Android if its only Kodi you want. The NEO U9 - does not have a Stable version of LibreELEC Kodi available for it.

The S905 MINIX NEO U1 does. You just flash LibreELEC Kodi to a Samsung EVO or Sandisk UHS-1 Class 10 micro SDHC, plug that in. Hold down the power button on the U1 box itself, count to 5 and it boots straight into Kodi. Pop the SD card out and reboot and you are running Android.

I recommend a Wireless Keyboard remote.  

 I was considering picking up a U9 though after reading through this thread I'm having some doubts. I have relatively simple needs in that I have my DVD collection on an external usb hard drive connected to my current box.  The media is 720/1080 in MP4 and the tv series are .ISO   Will I have a problem using the Minix U9 as an android player for this ?   Would I be better off running Libreelec ?  And should I get the U1 instead of the U9?

Also you mention 'Hold down the power button ... and it boots straight into Kodi'.  Does this have to be done each time you boot into Kodi ? 

Thanks...