Most likely, Brian is still very much retired and trying to live the good life, but it's not absurd to consider the idea that the F9 team will use digital technology to bring him back as well. That is, after all, the route they took to finish Furious 7 in the wake of Walker's tragic death. Rather than cut Walker's role from Furious 7 (he was about two-thirds of the way through shooting, according to production designer Bill Brzeski), kill his character off, or even scrap the project altogether, producers instead elected to use his brothers as stand-ins and finish his scenes by recreating his image with CGI tech. The bold move actually paid off from a narrative standpoint, and offered Fast and Furious' cast, crew, and fanbase a chance to bid a fond farewell to a beloved franchise friend.
That goodbye actually did involve Brian leaving his fast and furious family behind for good, riding off into the proverbial sunset with Mia and their kids (who may also be appearing in Fast 9, if Vin Diesel's past Instagram post is to be believed). It also involved specifically crafting that tear-jerking final scene for Furious 7. But tears, goodbyes, and "retirement" aside, Mia is officially charging back into action with her Fast and Furious family, and we can't help but wonder if producers might be eyeing some way to CGI Brian back into the mix as well — even if that does sound like a dicey (and terribly expensive) gamble even by Fast and Furious standards.
