Final Fantasy 9 is by far the culmination of the entire Final Fantasy franchise. In fact, Nobuo Uematsu, who mind you hasn't exclusively composed for the franchise since (he did compose for X but not exclusively) he himself said that it was his favorite project that he had worked on in the franchise.
I myself personally believe that the formula that square enix is searching for now can be found in FFIX. I won't drag this out but I'll be sure to hit on everything important.
To put it simply,
If you want to play an immersive game that only needs the use of a driving story, cinematics, and an astounding soundtrack all while remaining void of any needless voice acting, then FFIX is your game.
If you're in dire need of hopping on a chocobo and doing side-quests that are actually beneficial and possibly detrimental to enhancing already said immersive gameplay, then FFIX is your game.
If you like going on quests not just around the the world but to other planets or dimensions all in search of either secret bosses or ultimate weapons, then FFIX is your game.
If you like playing a game where there are actually alot of open world opportunities and it's just a matter of what to do first, all the while each opportunity possibly significantly enhancing already said immersive gameplay, then FFIX is your game.
If you like summons, assigned roles, each individual character having an equally engaging back story, assigned abilities, be it magic or support just everyone has their own individual strengths, specs, weapons, gear, no spamming what so ever, what you get is what you work with, all strategy, then FFIX is your game.
And honestly that is just the tip of the iceberg of what Final Fantasy IX has to offer. Engaging, I mean truly amazing story that will have you at the edge of your seat either cheering or ready to shed tears for each character, battle system is awesome, 4 chars per battle and since no one can share roles there's more strategy involved especially in late game battles, astonishingly immersive game-play. Honestly, VII had it too, it was cool but IX does it so well and a lot better as through out the game you take control of some of the other characters and see the story from their point of view, and there are brief moments when you control them and actually walk around in real time with them (Garnet notably). Also it should be noted that FFIX is the only final fantasy ever to have a 2 player option( though mostly for battles). Overall the game is phenomenal. If you have the time, pick it up probably online via PSN and play it. You will not regret it.