User blog comment:StrawHatDavid/Talk about Ep 590 and such/@comment-3075024-20130409050612/@comment-4605926-20130411105412

Hmmm, let me explain it to you as briefly as possible.

First of all, as AYET-san pretty much said already, it's not about Dragon's balls, but about Dragon Balls (mostly comparable to balls created from glass or something and definitely have nothing to do with a human and/or dragon's body). When all 7 balls are gathered, a person will be able to make pretty much any wish come true (including those you probably have in mind right now).

Over 9,000 refers to Goku's (the series protagonist) power level at the beginning of the series where it was still considered a fairly high amount (now it's probably in the billions or something if you're willing to compare that is).

In some way, you are lucky to watch this without having watched DBZ beforehand. The reason for that is because the DBZ characters have such overwhelming power that their display of strength in this episode appeared rather forced and ridiculous.