last update: finally uninstalling 9.0.1 and installing 9.0.1FP1 solves the issue.
I've upgraded to 9.0.1 FP1 SCC, community and proxy without issue. However, when upgrading the meeting server, IM crashes in the middle of the update. I've found this TN http://www-01.ibm.com/support/docview.wss?uid=swg21690056
but does not help. Furthermore, upgrading in console mode or web ui mode is not available for the sametime products.