Dio closes the Gold Saucer once Meteor appears. Meteor is there until the very end of the game!

So when am I able to go and use the Gold Saucer?

Help is most appreciated.

*POSSIBLE SPOILERS*

Dio eventually opens the Gold Saucer again when you get Cloud back. Keep playing the story until Cloud recovers and re-joins your party, then you can go back.

Yeah just wait a while.