If I were to leave a club to join another, do all the points ive earned for the old club come with me
No, all contributions made to a club stay within that specific club. If you go to a new club your contributions start at zero.
_CHAMPION
Thanks
Also if you return to the old club then you start off where you left your xp amount , example if you left at 2million then if you return again to that club you will start again at 2million ;-)