Bright light in the sky, in the '90s, what could it have been?
Gamma ray bursts are very rarely bright enough in visible light to be seen with the naked eye. This is why they weren't detected until there was a network of satellites looking for atom bombs. You didn't see a GRB.

If what you saw was Bright, and Fast it was likely to be a bright meteor, sometimes called a fireball. These appear as a very bright, fast-moving "shooting star". They are rare, but not so rare that it would be possible to identify a particular event from the information that you give.

A reflection from a satellite can look like a star that brightens and then fades. The Iridium satellites are well known for this though other satellites can also produce "flares". Iridium flares have been visible since the late 90s.

There are other mundane possibilities, but these would seem to be the most likely. Remember memory is a funny thing. After 20+ years thing that you "remember" might be different.