That's a misleading error. Yosemite and higher are too new to install Resolve 9 on.
Why in the world do you want to use Resolve 9?
All Resolve versions from 10.1.5 to current are available on the BMD web site:
https://www.blackmagicdesign.com/suppor ... and-fusionDownload and install something newer. On the web site, for any of the versions less than a few years old, the ones that say Studio require a Studio license, either a USB dongle or activation code. The ones that don't say Studio, or that have Lite in the name, are the free versions.
The version 9 you got with the Cinema 2.5K camera was the free version. The installer for that probably has Lite in the name. Unless you got a Resolve USB dongle with the camera. But pretty sure that camera did not include a Studio dongle.