Well, during World Boss I would recommend using characters who create clones. They don't have to have combos with each other - in fact, characters with a Chase that is activated with 10+ hits are probably best since the Nine-Tails is immune to all other forms of Chase.
I also recommend saving up some coins and spending it on ANBU Support - it probably won't seem like much but if you have enough money if gives you +30% your stats.

Just make sure the Mysteries are really strong and your Equipment is fully Strengthened!