Is 1 and a half day in Nauro too short?

I plan to go to Nauru, but the only way to get there is by Our Airline. They fly from Brisbane in Australia once a week (saturday morning), and fly back to Brisbane once a week (on monday). Since the flight is going really, really early (1:00 AM), and arrive 8:50 I think i'm going to be really tired on the saturday. I know it only takes 20 minutes to get around the whole island, but is this enough time?

The reason I want to go to Nauru is because the country has an interesting history, and I always liked small countries.

If you are not to tired on Saturday - you will have 2 1/2 days - and I think it is time enough for this small island. I have my ticket already for Sat. Dec, 12th.