We've got an interesting rumor regarding the plot of Star Wars 9. This particular rumor has been floating around online for a little while now, but it seems to refuse to die. Whether or not it has any truth to it at this point is up in the air, as it has yet to be substantiated by anyone officially working for Lucasfilm, or anyone related to the production, remains to be seen. In any case, it looks like the First Order may have a traitor to deal with.
Warning: possible spoilers ahead for Star Wars 9. Since this isn't just a fan theory or something of the like, we must caution that this could spoil elements of the movie's plot, so those wanting to avoid spoilers may want to turn away. Also, again, it's merely a rumor for the time being and should be regarded as nothing more. That all having been said, it looks like none other than General Hux (not to be confused with General Hugs) will betray the First Order in the upcoming finale to the current Star Wars trilogy.
Per the rumor, Kylo Ren will be seeking out a mole within the First Order who has been dishing out secrets to the Resistance. It turns out that mole is Armitage Hux, who is portrayed by Domhnall Gleeson. But the question, why would Hux do such a thing? It's not because he's suddenly had some major change of heart. Hux still craves power, and that's the point. He's hoping to discredit Kylo Ren, who is now the leader of the First Order, given Supreme Leader Snoke's untimely death in The Last Jedi. With that, Hux would like to take over as the new Supreme Leader himself, once the organization turns on the man formerly known as Ben Solo.
It's the reasoning that actually makes this theory pretty believable. We're expecting that at least a few years will pass between The Last Jedi and Episode IX. Kylo and Hux have always clashed a bit and, after a few years under his rule, the angry general may have had just about enough. While it would seem like a bit much for Hux to have a full-on shift in character, leaving to join the Resistance entirely, helping them out just enough to end up helping himself is very much on-brand for the character.
Should this come to pass, it would actually mirror some of what happened on Star Wars Rebels with the character of Agent Kallus. The character was a high-ranking official within the Empire before feeding intel to the early Rebellion. Eventually, Kallus fully shifted and became one of the "good guys" (depending on your perspective). While that element surely won't exist for Hux, there is precedent for such a thing in the Star Wars canon.
Beyond what rumors are floating around, details are scarce in terms of official plot details. J.J. Abrams is back in the director's chair and he, as well as the brass at Lucasfilm, are keeping things locked down for now. Expect to get some firm details during Star Wars Celebration next April. Star Wars Episode IX is set to arrive in theaters on December 20, 2019. This was previously reported by CinemaBlend.