It really isn't. I replayed FF9 last year, and I feel like you spend 10 hours throughout it just waiting for battles to start up and end.It's slightly slower than the other games because it was pushing more graphics and driving the PSOne to its limits, but its slowness tends to be way overblown on GAF.
Those looong drawn out startup camera pans were clearly only there to mask model loading. And they're terrible.
The in-battle speed is a relatively minor issue comparatively.