The list continues to grow daily of officially supported devices for CyanogenMod 12. The Nexus 9 is the latest device to be graced with an official build. The Nexus 9 was the first tablet to be released with Lollipop, but if you want to customize your device your options are limited. With Cm12 you have the ability to add a custom theme, change your settings toggles, change your nav bar, and much more. You will need to be bootloader unlocked, and have a custom recovery installed in order to flash CM12. You will also want to be sure to grab the latest LP Gapps so that you have access to the Play Store. Also be sure to make a backup of your Rom prior to installing CM so that if you don't like something you can always revert back to your previous setup.
via CyanogenMod