Newest CyanogenMod nightly adds support for 4 new devices, HTC One M9 among them
Well, today, owners of 4 more designers will have the freedom to join the ranks of Cyanogen fans, if they so desire. The development team has released a new nightly build, which now has versions for the HTC One M9, Nvidia SHIELD Portable, Nvidia SHIELD tablet, and the less-famous ZUK Z1. Remember that the proper build for your device can be found when looking for the proper codename – in the case here, the One M9 is “himaul”, the SHIELD Portable is “roth”, SHIELD Tablet is “shieldtablet”, and the Z1 is “ham”.
Nightly builds are not stable, so flash at your own risk. If you don't feel that much adventurous, you may want to wait until the next stable Cyanogen release hits the download page, though, it's still not guaranteed that support for the new devices will be included with the stable version. C'est la vie!
source: CM Download page via Android Community