Where to find iWork 09 full version?

The servers that provided the unlock code for iWork '09 are long dead & Apple support will not be able to help you.

There are no legitimate download sources for iWork '09 (trial or otherwise). You may still be able to purchase the retail box from third-party sources such as Amazon or eBay. I did not see any available on a search of Amazon but did find some with this search of eBay. You must be sure it is the retail version, not the trial.

Before installing the retail version of iWork '09 you need to delete the trial & then reinstall from the boxed DVD or the Mac App Store. The files to delete are the iWork ’09 folder from the main HD > Applications; the iWork ’09 folder in HD > Library > Application Support & the individual iWork application plist files found in HD > Users > (your account) > Library > Preferences for each user.

Then, once you have installed the retail version of iWork '09, you to run the update to version 9.3 before running any of the applications. You can download the standalone updater from this page.

Just a footnote. The retail iWork '09 installation will work in all revisions of macOS High Sierra (10.13.n), but fails in macOS 10.14.0 thru 10.14.4. It resumes working in macOS 10.14.5, and later Mojave updates, but is a dead duck in Catalina and Big Sur due to its 32-bit limitation.

Documents created in Pages, Numbers, and Keynote applications introduced after Oct 2013 are not directly backwards compatible with the iWork '09 suite of applications. If you do not have these installed, you can open these documents in Pages for iCloud, and download it as a Word document.