you can import any model or texture into fifa and say it will display, but by saying compatible it means to say it works correctly. This is not compatible:
If you see correctly the face texture is mapped completely different from 07/08, furthermore it can't find the arms because the respective mapping does not exist in the texture.
Unless you remap every .o model for every face you import, you might be able to have your face show up in game, but doing so would be very difficult. As far as arms go, you would have to format the face texture to include the portion that is being cut out, I think the new face textures are 512x512 instead of 512x256.
Kits is the same, the mapping is gonna be off, and you would have to remap the player model to get it to display correctly and import all fifa 07 kits, you can't have both fifa 09 and fifa 07 kits.
As far as hair goes ea has decided to attatch a tga file to the hair texture to get the transparency and quality better in fifa 09, so you will have to do the same with all the hair textures.
Like I said it is completely different and to port all the older stuff into the game it would require you to create all new stuff which is in my opinion futile, good luck on trying to do that, but I stand by what I say, you need to brush up on fifa 09's new graphics templates to learn how to mod it properly