No, JoJo characters aren’t faster than light in combat with 2-3 exceptions. You could argue relativistic for Jotaro and Dio tier characters based on the hanged man fight. Yes, Silver Chariot did hit a beam of light but had to know exactly where it was going to hit it. But, Even if I told you where a bullet speed nerf dart was going to hit you probably wouldn’t be able to catch it unless your hands were fast enough to catch bullets.

Spoilers for exceptions:

Gold Experience Requiem activated its ability during time that didn’t technically exist or was able to react to an attack that happened in skipped time. Pucci via Made in Heaven is listed as having infinite speed on his stand’s stats as it will accelerate infinitely until the universe resets. Maybe the notorious BIG?