We just finished moving MCA over to Minecraft 1.9 today. It is now available for download!
It will require that you are running the latest version of Forge for 1.9. Currently, that's version 126.96.36.1995, but a higher version should be fine. Keep in mind that Forge for 1.9 is under heavy development and doesn't have an official public release just yet. Because of this, MCA for 1.9 is marked as a BETA release. Performance and stability can't be guaranteed just yet, so keep regular backups of your saves.