MP9 to PT10 or 12 projectmix

[skiffle]

Hello,
I am currently running PT 9MP with Projectmix I/O
I am about to upgrade to PT 10 or 12, i would like to keep my PT MP9 as i have been recording poets and spoken word and sometimes a client will want to change or tweek something, so i'd like to be able to access the projects in MP9 for that reason and not have to uninstall MP9 altogether.I want to upgrade to 10 or 12 to get things like Clip Adjust etc to work on my songs and music and i'd also like to edit without having to be hooked up to the projectmix like i have to be to open MP9. Is it possible to run both MP9 and the new upgrade on the same Macbook pro OS X 10.6.8, or is there a way of opening MP9 projects in PT 10 or 12, i've been told that PT 9MP is different than PT 9. Ideally it would be great to shut down one and open up the other depending on what i want to work on!
Any help on this issue would be much appreciated, Thanks!
Skiffle