I'm currently watching Naruto on Netflix and noticed that there are 9 seasons, now my first question. The episodes available on netflix are all complete, so that no episodes are missing. Now to my real question, I saw that naruto shippuuden is also available, but is not available on Netflix. What is this series, it's just a prequel that tells the story or something else?
As far as I know this is complete.
Shippuden simply continues the story after a jump in time.
"Naruto" has 220 episodes, all of which are available on Netflix.
"Naruto Shippūden" is the sequel to the story and has 500 episodes. In the original work, the manga, it is a coherent story, only in the anime it is divided into the two series.
You can watch Shippūden legally on TVNOW, Amazon Prime Video, Crunchyroll or as DVD / Blu-ray.
https://www.tvnow.de/.../staffel-1 (currently up to episode 423)
https://www.amazon.de/...07Q7WVFQW/ (currently up to episode 450)
https://www.crunchyroll.com/...-shippuden (complete, with subtitles)
With Netflix it should still come, but the date has been postponed several times.