If you have IHG status/points there is a HI Sepang (newly opened) which is about 15 - 20 minutes to the airport. Do you land at 8pm or you expect to get to the landside at 8pm? Last time it took us almost 2 hours from landing to getting our bags to the landside - the immigration was so slow and there were multiple widebody jets arriving at the same time.

Yeah but then why? You won't get the lounge access as the happy hour would be finished by the time you get there and you won't be able to enjoy your breakfast as you have to leave before they start anyway.

I'd stay in the airport or book a room at KLIA.