How to open raw Sony a9 photos in a Mac Pro

If you are referring to the Sony Alpha 9, it has camera RAW support in Big Sur 11.7.9, macOS Monterey 12.6.8, and Ventura. If your Mac Pro is running an older operating system, press the option key and Apple menu to select System Information : Software : Raw Support and scroll to Sony, and check if the Alpha 9 is present. If not, Apple does not make camera RAW support retroactive to earlier operating systems.

What application are you opening the Raw files with?

Photos uses the macOS Raw compatibility libraries. Adobe applications use Adobe's own code, which is built into the Adobe Camera Raw plug-in (for Photoshop and Photoshop Elements), and hard-wired into the Lightroom and Lightroom Classic applications.

Adobe's compatibility list includes the A9 Mark II, but not the original A9.

https://helpx.adobe.com/camera-raw/kb/camera-raw-plug-supported-cameras.html