if your Poser P9 was a download, not a hardcopy. you will likely have to re-purchase P9 as a Mac version, unless you bought the extended download service.

only the boxed Poser discs come with both Mac and PC versions.

as BB said, copy your runtimes over to an external drive. a new mac should recognize it straight away. then its just a matter of linking the runtimes to the library.