FFI -> Rat's Tail for job upgrade
FFII -> Can pick weapons/magic and skill them up
FFIII-> Crystals unlock job
FFIV -> Preset jobs but leveling unlocks abilities
FFV -> Crystals unlock job
FFVI -> Set jobs
FFVII -> Materia
FFVIII -> Draw/GF system
FFIX -> Set jobs
FFX -> Set jobs
FFXI -> Can change jobs 6 avalible at first 14 unlockable ones
FFXII -> Licence board or in the case of zodiack job's are selected and licences are gained from smaller boards
FFXIII -> Paragam System
FFXIV -> Weapon is your job advanced avalible through questing

Yes some of them use same job system but others are unique every FF has things that make it different <3 Chocobos, Cactaurs, Summons, and job names make them similar