I wouldn’t worry about it. There’s going to be a huge presence there for IX. All the usual suspects will be in attendance, JJ, the cast, Kennedy. I doubt you’ll even hear a single “Boo!” from the crowd.
You’re right. The fans who don’t like the new movies probably won’t go. But anything is possible. I know that EA got booed last year at the Battlefront II panel, but then again, tons of us, including me, were not fans of EA’s Battlefront reboot.