I assume it's working fine on the MAC but he didn't have much time to test it out. If it works on the PC I would expect the behavior to be the same on the MAC with no issues. I have yet to figure out racks so I fully understand what's going on and how to set one up from scratch. A good video tutorial would be great for it because of how much complexity you can do to it. I love the expansion to a mixer setup as well in it and other racks for each track so you can adjust each individually as needed. But again, I have not delved deeply into this. I'd love to learn them more so I could come up with some racks to share.
As for working on an '09 MAC I would think that would be just fine, but not owning one can't say for sure. My buddy has an older MBP and it works fine with Live.