Yes, the jib luff must be tensioned properly and will effect sail shape and therefore pointing. The small luff tension line tensions the jib fabric and is mostly a set-it-and-forget-it adjustment. Put up the jib and fully tension the jib luff wire (halyard). Then tension the luff tension line until it feels "nice" and any wrinkles come out. Don't honk down on the tension line or try to do this with a loose jib luff wire. If the tension line is too tight, the sail fabric will begin taking the halyard load and the jib fabric will stretch and possibly tear. The factory installs the tension line at the jib head in which case you need to tip the boat over to get at it. The tension line can be moved down to the tack if you prefer.

I don't mess with jib batten tension much. I tension them enough to pull out the wrinkles and punch a little shape in. Too much tension is probably worse than not enough. I will back off the normal tension a little on very windy days (flatter sail).