Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from O'ahu to Perth as you normally would.
Due to multiple factors, expect to potentially pay more when booking in November. For low rates, February can be a great choice for travel to Perth. Flights to Perth from O'ahu in February are about $1,088 on average during February, but can be found for as low as $712.