My Experience Arriving at Fukuoka Airport:
Information on the Arrival Lobby and Facilities
Unlike other international airports, Fukuoka Airport is not open 24 hours. The airport closes after the last flight arrives. Last flight arrives around 9pm. Airport closes after passengers from the last flight leaves the airport.
Since the airport is not open 24 hours, the shops close earlier than the airport closing time. The foreign currency exchange counters close at 9pm and the HIS counter where you claim Klook purchases close at 630pm. Yoshinoya, the only restaurant in the arrival area, close at 8pm.
MY TIP: If you're arriving on an evening flight like the Cebu Pacific flight from Manila that arrives at 7:30 PM, pre-purchase yen at your local bank before you leave and buy sim card at lazada because it's unlikely you'll be able to arrive at the airport on time to reach the foreign exchange counter and HIS counter during their operating hours.
Also, make sure to have the screenshot of the immigration qr code and customs qr code ready. Once you get off the plane, the Japanese airport staff will herd you so fast through immigration, you will not have enough time to look for it.
Airport WiFi is free and very easy to access and connect to.