@ASSpirine: Manga readers know something about your "why" question, but cannot say. Suffice it to say that the Kyuubi isn't all that it seems.
Even though this isn't such a satisfying answer, the Third Hokage seemed to agree, and tried to protect Naruto from his past. Heck, remember that the Kyuubi met Uchiha Madara at some point in the past.
Edit: finally watching this. I hope it is as good as I hoped.
That stuff with Enma and Sarutobi is filler. In the manga, Sarutobi suggested they go peeping at the baths together.
I pictured Jiraiya's mentor toad a different color.
Damn, Yahiko sounds like he's 20.
Also, Jiraiya became a missing nin when he decided to leave the village and teach the kids. So being a missing nin isn't that bad. It's a label villages use on people they want to distance themselves from politically.