You know a franchise has run out of ideas when it sends its characters to space. "As long as we obey the laws of physics, then we'll be fine," Tej Parker (Ludacris) tells Roman Pearce (Tyrese Gibson) as the two prepare to literally drive a car offworld — an odd statement, considering it might be the first time in nine movies that they even acknowledge physics and the laws that govern it.
F9 is no exception. Right off the bat, Roman finds himself in a predicament that even Wile E. would find preposterous. Following a miraculous escape, Roman begins to suspect what Cipher (Charlize Theron) seems to already know; that they are all characters in an action movie. Sadly, the film doesn't pursue this direction which would be far more interesting than the Long Lost Brother tale it settles for.
It turns out that Dom Toretto (Vin Diesel) has a brother, Jakob (John Cena). Like the laws of physics, Dom had never let on that this brother ever even existed. Thus, we get a series of expository flashbacks to provide some background for this new character; you know, so that it doesn’t appear as if they just pulled him out of fucking nowehere.
These trips down amnesia lane are what truly sinks the movie. F9 uses the format popularized by The Godfather Part II, in which Al Pacino plays Michael Corleone in the 'present' and Robert De Niro plays Vito Corleone in extended flashbacks.
Now, Diesel and Cena are no Pacino or De Niro, but they are two unique individuals endowed with clearly defined personalities and who happen to ooze charisma and self-confidence. In comparison, the actors who play their younger versions are such non-entities that they almost make a good case for digital de-aging (almost). As a result of this, F9 loses all the momentum it has gathered in the contemporary scenes every time it looks back.
Moreover, Cena is too obviously a Red Herring; there's a reason he played a 'heroic' character in WWE for roughly 15 years, and it's because he couldn't be a convincing villain even if his life depended on it.
Meanwhile, skilled performers like Kurt Russell, Shea Whigham, Michael Rooker, and Helen Mirror are wasted in peripheral roles (not to mention Theron, who spends most of her screen time literally locked inside a transparent box, leaving us to wonder what she does when she has to go to the bathroom), the filmmakers seemingly operating under the impression that they must perforce make room for each and every character who has ever made an appearance at some point in the series.
Apart from those already mentioned, we briefly see Lucas Black, Don Omar, Bow Wow, Jason Tobin, Gal Gadot, and Jason Statham in a cameo during the closing credits (unseen by me because once the credits roll, I’m outta there). About the only exception is of course Paul Walker (but not, as one might have reasonably expected, the one who had supposedly died in an explosion in a previous installment), whose character, from what we hear, has been reduced to babysitting Dom's son and his own. Is that the true Fate of the Furious?