Is there a need to upgrade?
It's your choice. There are no new features at the moment or bug fixes.
The OS and Amahi are a bit faster.
Please note that Fedora 21 and Amahi 8 are in
Maintenance Status ONLY.
What that means all Amahi updates (i.e. platform, applications, etc) have been halted. Also Fedora 21 is now in Sunset, which means no OS updates will occur.
The benefit of upgrading is that you will be on the latest Amahi release and Fedora OS. All security patches for the OS will be available and all Amahi applications will continue to receive updates. New applications will be released on Amahi 9 ONLY as well as platform enhancements/bug fixes. This will also make the path for upgrading to Amahi 10 easier.
As I said it's your choice.