Where does “Kyushu” come from?

Kyushu comes from Japanese 九州, a compound of 九 (kyū, "nine") and 州 (shū, "province").

Ancestry of “Kyushu”, step by step

Step	Language	Word	Meaning
1	Japanese	きゅうしゅう	—

Kyushu — Etymology, Origin & Word History | Etymology Explorer