Hi agencep
Did you save your old psa.key (/etc/psa/psa.key) first?
Although the old 8.6 psa.key won't work with 9.0, having it to hand will make the process of converting it to 9.0 key easier (or even possible). If you didn't explicitly save the key, but did a plesk backup, you can use the 'pre9_backup_convert' script that you have probably seen mentioned in the forums - it is part of the plesk 9.0 installation i.e (on my CentOS system):
Code:
# rpm -qf /usr/local/psa/bin/pre9-backup-convert
psa-backup-manager-9.0.0-cos5.build90081208.07
If you do run the pre9-backup-convert your old 8.6 key will probably be located in /var/lib/psa/dumps/converted_key_0901260135.tgz (although it is called 'converted key' it is actually just your 8.6 key and won't work with 9.0).
NB: psa-backup-manager isn't included in the default installation of Plesk 9 (not much is), so you may need to install that first.
I ran into the exact same problem as you, what I did is reinstall my server again. This probably is not necessary, but for the 20 minutes or so it took, it was probably worth it to avoid any potential problems caused by uninstalling 9.0.
Then once the OS was installed, I did a default (virtually minimal) installation of 8.6. I chose a minimal install because it is quicker and there is less to conflict with the later installation of 9.0. Next, I installed the 8.6 key (you might be able to use the key retrieval system at this point, if you didn't take any backups). Finally you can upgrade to 9.0 (I used the same autoinstaller script that I used for the 8.6 installation). The upgrade will automatically convert your licence (although it doesn't make any changes to the '/etc/psa/psa.key', so I'm not entirely sure how that works, I guess it must register you with Parallels' authentication/activation system as being a 9.0 user).
I suspect that you could now do a fresh install of 9.0 and the key would work - however I can't guarantee that as I didn't try it. My upgrade went remarkably smoothly and as it was 3 am in the morning by this point, I was happy to leave it be.