Unfortunately very few things are cross-compatible between the consoles. PS4 has its own versions of FF7 and 9, as far as I know the PS3 emulates PS1 games, and doesn't have actual ports the way PS4 does. What games are you wanting to transfer? I can't remember if FFX works, but since the vita and PS4 versions are cross compatible, it might (I can't even remember if FFX got a re-release on PS3)