Have there ever been other TV shows or Films that told a similar story to the new 90210 show?

I am a huge fan of this practice. TVTropes calls it As Himself and has the hilarious apocalypse comedy This is The End as a screenshot.

This trope is when a real-life celebrity or famous figure is playing a fictionalized version of themselves, as a main character or recurring character. This is mostly a television trope, but there are film examples. For shows that take place in an alternate Hollywood, such as Curb Your Enthusiasm, Entourage and The Larry Sanders Show, this is the norm. It would be hard to believe it's Hollywood if you'd never heard of any of the "stars", would it?

This real celebrity is playing themselves, but they are inserted into fictional circumstances, play alongside clearly fictitious characters and sometimes have fictional backstories in relation to those fictional characters. This differs from an Autobiographical Role, where the celebrity is playing themselves in the actual story of their life.

Another example was James Van Der Beek in Don't Trust the B in Apartment 23*. My examples are comedy but any fiction really fits the trope.

In 2008, ITV aired a pair of shows that worked like this: Echo Beach, a soap opera, and Moving Wallpaper, a comedy-drama show about the (mostly) fictional production staff of Echo Beach. The two shows aired back-to-back, with each week's Moving Wallpaper episode depicting the production of the Echo Beach episode that immediately followed it.

Actors from Echo Beach regularly appear in Moving Wallpaper, playing their real-life selves. The two most prominent would be Martine McCutcheon and Jason Donovan, who play the central characters of Echo Beach, and appear as themselves in Moving Wallpaper. Characters from Moving Wallpaper are also listed in the credits of Echo Beach, as screenwriters and so on.

It was all pretty clever, but unfortunately ITV cancelled Echo Beach after just one season. The second and final season of Moving Wallpaper was about their attempts to get it back on the air and, having failed that, their attempts to produce a zombie series called Renaissance (for which a pilot was released online).

Although viewers didn't get to explore it, because the series was just cancled (and this only beats the 90210 revival by a few months), The OA's second season ends on a mass cliffhanger where,

Prairie/The OA travels to yet another dimension/parallel universe, but one that is not as quite as parallel, as the previous one featured during the second season. The scene transition with Prairie levitating into the sky, only for it to suddenly appear as thought they are filming on a TV or movie Set! Prairie falls from an accident with the crane that was lifting her. Jason Isaacs, who previously played Dr. Hap on the series, and Prairie's nemesis, comes rushing to her side and it's is revealed that he is now "Jason Isaacs", an actor that plays presumably Doctor Hap, and in this reality he's married to "Brit Marling", who may be "playing" Prairie.

Generally anything that exists inside (in-universe) and outside (Out of universe) of itself within one work is considered some type of "Meta" including this 90210 revival:

In BH90210, Fox's meta-revival of Beverly Hills, 90210, the series' original castmembers play heightened versions of themselves as they try to mount a reboot of their '90s teen soap. The hourlong dramedy is full of Easter eggs for fans — literally, as Jennie Garth has a nightmare about exchanging an egg — but the series is also full of tongue-in-cheek references to the stars' real lives.

But m1gp0z's "As Himself" trope is more specific as the type of meta it is.

One of my favourite examples of this recently was the Legends of Tomorrow episode called Guest Starring John Noble. John Noble was the voice of the big bad of that season and during this episode, one of the main characters was watching one of the The Lord of the Rings films (also starring John Noble). It was noted that the character in the film sounded a lot like the big bad so they travelled back in time to when the LOTR films were being made, met John Noble and tricked him into reading some lines that they could then use to trick the big bad’s accomplices.

Possibly episode 6.15 of Supernatural: The French Mistake, where Sam and Dean literally break through the fourth wall (well, window) and find themselves on the set of Supernatural and must find a way to return themselves to their correct reality. They do this by portraying their actual actors and spending their hard-earned acting money to overnight ancient relics for a ritual, all while making in-jokes about the show's production.

I haven't seen BH90210, but from the description - maybe Being John Malkovich might be an example. Actor John Malkovich plays himself there and the plot revolves around other character finding a portal to the famous star's mind.

Also, in Bandersnatch

in one of the endings the main character finds himself literally being an actor of the eponymus TV show.