It is. I went through Final Fantasy IX a while back (PlayStation version too) and it absolutely holds up just as well... no perhaps even better, than it did all those years ago. I was worried of the opposite but no, I guess it just shows I feel something is lacking in modern games, even if i truly enjoy them too.
The PlayStation era titles (VIII and IX especially, VII less so since it's not as good on graphics) still hold up in visual style, but they do suffer from displays having passed them by due to going to much higher resolutions, so you're stuck between filtering/CRT shaders or AI upscaling, which is passable, but VIII and IX especially deserve some modern treatment due to them being the only two that haven't gotten any re-releases, come on Square Enix! Yes, I know Final Fantasy VIII got a remaster but it was a poor excuse of one, and Final Fantasy IX got nothing at all. Everything else in the series from XII and prior got re-releases, pixel rematser, complete remakes, and sometimes multiple ones.
I definitely intend to play through Final Fantasy VIII again eventually, since it's on my favorites and it's probably been the one I haven't played in the longest so it's definitely due (and I've been listening to a lot of its music recently), but I've got too many upcoming games so it won't be anytime soon I'm afraid.