Hi Lauren,
All of 8 temple has shuin stamps. Most of them have only one but Dazaifu and Nanzo In and Miyajidake has several.
Especially Miyajidake has 8 stamps but you need to go 8 different small shrines in MIyajidake shrine.
I hope I can answer what you would like to know!
Enjoy your trip in Fukuoka!