Who is the 8 year old king mentioned in the bible?

Answer 1

Josiah. See 2 Kings 22:1.

22:1 Josiah was eight years old when he began to reign, and he reigned thirty and one years in Jerusalem. And his mother's name was Jedidah, the daughter of Adaiah of Boscath.

Another King was Johoiachin as told in 2 Chronicles 36:9. Jehoiachin was eight years old when he began to reign, and he reigned three months and ten daysin Jerusalem: and he did that which was evil in the sight of the LORD.

But according to 2 Kings 24:8, Jehoiachin waseighteen years old when he began to reign, and he reigned in Jerusalem three months. And his mother's name was Nehushta, the daughter of Elnathan of Jerusalem.