Yes you can convert the memcard image back to a vgs memcard although make sure you're using the ff9 patched version otherwise ff9 will report the saves as corrupted. Epsxe can directly access vgs memecards without the need for converting but it can corrupt them so I usually make a backup copy first.
There are a couple utilities available for converting memcard images. Aldo has written one for just about every possible eventuality. I of course prefer PSXGameEdit (
http://moberg-dybdal.dk/psxge/). This was originally developed for people who own Dexdrives but does a fine job of allowing you to manage your memory cards. A few features
-Individual game save and load
-Game hex editor
-multiple memcards type support (saving and loading)
-region converter
It’s freeware too.
The only hangup is that it that you have to change the extension on vgs memcards to .vgs otherwise it doesn’t recognise them (made to load Mac vgs memcards) and you have to change it back from .vgs to .mem if you want to use them in vgs. If however you were to use a hex editor on the program and change all instances of vgs to mem in the psxGamEedit.exe (remembering to be case sensitive) it could quite possible(

) recognise the pc format version without the need to rename all the time. I don’t think the author would approve of you editing his code however.