Finally, thanks :)
For the upgrade 9.0.2 -> 9.0.3 is used online update and it works :) That was one of the biggest features I missed in Intellij. Always download complete installation was (compared to eclipse) more complicated.
The only thing which is a bit confusing is that /opt/idea-IU-95.66 is still there instead of /opt/idea-IU-95.425 on disk. But I guess this folder naming will change for IntelliJ 10.