Final Draft 10 and Final Draft 9 are compatible with Yosemite. The FD10 installer is HERE and the FD9 installer / updater is HERE.
Final Draft 126.96.36.199 is also compatible with this operating system but it will not be updated if there are issues.
Final Draft 7 / 6 / 5 are not compatible with Yosemite.
If you own Final Draft 7 / 6 / 5 and you want to run Final Draft on a Yosemite computer, you will need to upgrade to FD10. This upgrade is not free. Click HERE for more information on purchasing the FD10 upgrade.