"The meeting is between 8 and 9 o'clock." is the correct option. When using "at" you need to talk about a specific hour. Example: "I'll be there AT 8pm." I hope this helps!

The first sentence is correct. If you wanted to use "at" in your sentence, you could say, "The meeting is at 8 o'clock and lasts until 9 (o'clock)."

1) the meeting is between 8 and 9 o'clock is the correct one No at ;)