Not sure if someone already stubbled on this but, heck. I'm 95% sure that the jitsu that Jirayi told naruto to never use is the same Jitsu that Gaara used. Where he brought out the raccon, the beast within him. Think about, if Gaara was taught how to use it, why wouldn't Naruto be taught it too? Heck, for the record, I really want to see how much destruction the nine-tails itself can blow in matter of seconds. Better yet, I want to see how the fight with the fourth and nine-tails went.