I just released an IDEA 9 version of the mks vcs plugin, it's available in the plugin manager.
List of changes can be found here : http://code.google.com/p/ideamksplugin/issues/list?q=label:Milestone%20label:Release0.8&can=1
Main changes include :
- don't trace the mks password in idea.log
- allow to open the mks change package associated to a change list from the IDEA changes view