It generally runs up to macOS 10.12 (Sierra) . It will not run on newer macOS versions like High Sierra or Mojave due to the removal of 32-bit support and core architecture changes.
The method for downloading the 9.1.8 update depends on how you originally purchased Logic Pro 9: logic pro 9 update 918 download free
How can I update Logic Pro 9.1.6 to 9.1.8? - Apple Community It generally runs up to macOS 10
Improved content downloads and installation stability for OS X Lion and Mountain Lion . If it isn’t showing up, ensure your application
If you are using an older browser (like an old version of Safari) and the download button doesn't appear, try using a newer version of Firefox or Chrome to access the legacy support pages. Key Improvements in Version 9.1.8
If you bought Logic Pro 9 through the Mac App Store , the update is usually handled through the Updates tab of the App Store app. If it isn’t showing up, ensure your application is named exactly "Logic Pro" and is located in your main Applications folder.