Well, Mac OS 9 doesn't support MFS at all. Period.
You can only go up to 7.6.1, and even at that, you only have read-only support.
I've read of something called MFSLives or some such that you might try out. I'm not sure if it works on 9 though (it is aimed primarily at Mac OS 8.0 and 8.1 I think).
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