@gossamer: You can install either the regular Kodi from the Play Store or you can install Zidoo’s own version of Kodi which they call ZDMC. You’ll find the link to the ZDMC installer on the Zidoo website here: https://www.zidoo.tv/Support/release_apk.html
Did I make a mistake in purchasing this with the intention of using it with Kodi?
I’d really like to stick with CoreElec. I’m familiar with the hardware list, but it’s simply a list of processors, not necessarily something I can find on Amazon. Ideas for a chipset/hardware combination that’s equivalent to the Z9X that provides 4K?
CoreELEC will never be compatible with Zidoo devices, they use a chipset not supported by CoreELEC, so if you want to stick with CoreELEC you need a different device. I used to use a Zidoo Z9S but am now using an Odroid N2+ running CoreELEC and find it works very well playing all my locally stored music and video files up to and including 4K with ATMOS or DTS-X reliably.