Hello,
If you get the DEMOAC, with the 9S08AC60 top board, you can run your 9S08AC code on it.
If it is written in C, there is a good chance that it will work the first time you replace the 9S08AC60 with a MCF51ACxxx.
If you develop your code using a DEMO9S08AW60 board, you would probably have to rewrite and change some modules in order to get it to run on the DEMOAC board.
Regards,
Ake