It's not possible and does not have to be possible, if he is using MTA's default account system. When player joins, he is a guest, not logged in. How will you get his account data (points)?
So I guess TAPL is right, onPlayerLogin has to be used.
The OP didn't say he's using default account system but did say he wants to load the points when the player joins, so I just sent him the right event for that.