Adobe officially ended support for Acrobat 9 in . This means no security patches have been issued for over a decade. Since PDFs are a common vector for malware, using an outdated reader or editor like version 9.0 exposes your computer to modern exploits that the software is unequipped to block. 2. The Activation Server Issue
If you do not need the ultra-heavyweight 3D and CAD capabilities and just want to edit standard PDFs without paying for a heavy subscription: adobe acrobat 9.0 pro extended free download