you could try with a kodi 17.6 fork on your U9 ( recommend WBMC) and just transfer a single video file to the minix internal memory ( if enough space) or usb stick and try playing that.
I now use Kodi 18 and use the Aura Skin ( very nice and easy to use) which is 18 compatible
download skin from github....
https://github.com/jurialmunkey/skin.aura/tree/Leia
worth a whirl
Now it's getting realy complicated ...
I installed WBMC, tried both 17.6 and 18 and
both is working with my U9. I getting 4k output to my TV, but I have to choose 4k-smpte. It doesn't work with the automatic settings wich give me 4k 60Hz.
But, when I choose 4k smpte, I get 4096x2160, and not 3840x2160 and i wonder why?
If I look here
https://en.wikipedia.org/wiki/4K_resolution it says that 4k SMPTE is explained as "A resolution of 3840 × 2160 (UHDTV1) ". Why do i get 4096? And what result is it giving me? My TV has a UHD resolution (3840x2160) but when i choose 4k SMPTE i get 4096x2160?? Do i get wrong perspective, or what is happening? My TV has a specified resolution of 3840x2160 and I'm using media with resolution of 3840x2160??
The upside of using my U9 is that i get HDR working. I don't get HDR on my U1, but i suppose that is correct, and by design. In a normal viewing distans, i think HDR is giving more benefits for the picture than UHD vs HD.
So, as a summing-up, do I get any disadvantages of using 4k-smpte, and what I can see, 4k but "wrong resolution"? Is it "wrong" to run 4096x2160 on a TV that have a specified resolution of 3840x2160?
My conclusion is that i stick to my U9 with 4096x2160 and HDR, instead of my U1 with 3840x2160 and without HDR! What do you think guys?