This program, which I am using in what amounts to a perpetual demo mode (no printing or exporting, basically), works fine in every aspect in which I've used it under Crossover 9.
I can allocate subjects to classes and teachers, work in a Week A-B environment, generate and test timetables, and basically do everything I need to do using aSc TimeTables. There doesn't appear to be a speed penalty compared to when I used to use the app in Windows XP, Vista or 7. Indeed, on a MacBook Pro it's quite quick.
In short, I have no difficulties with the program as I am able to use it now.