im making a fighter and im wondering if i should put some points in intelligence... ?
or boost strenght , dexterity , and constitution instead ?

Yeah, stick everything on STR, DEX, and CON. Who needs INT and WIS when you've got a BIG SWORD and HAMSTER. Right, Boo?

Two suggestions:
Try to put 6-11 points in intelligence. Under 6 points and you die with one hit from certain mind attacks. Every five points past 6 you can survive another mind attack.
Try to put 8 points, or 15+ points in wisdom. Under 8 points you lose resistance to confusion, charm. 15+ you gain resistance to confusion or charm.

Definitely get 18/91+ 18 18 in strength, dex and con. Keep testing to see if you have an 18/00, it's worth spending an hour or more rolling.

Con really doesn't play such a big role in BG2. My fighter's got fourteen con and still ended up with around 110 HP. Dualled at level twelve, mind.

Still... 18 con = 4 more hp per level through 9= 36 more hit points than someone with say, no constitution bonus.