Nine's Father was a member of the Garde.
He would have been raised by his grandparents from a young age while his parents trained their legacies. He would have been assigned a Cêpan to help prepare him for the arrival of his Legacies. He and Nine's mother would conceive a child who was intended to become a Loric Elder.
Sandor told Nine that his father was a Joust Champion, presumably the reason why Nine was left the Joust Rod in his Loric Chest.
Nine's Grandfather mentioned that Nine was all he had, suggesting that his parents were not alive. If this is not the case, Nine's father, along with his mother, would have certainly been killed in battle, attempting to prevent the Mogadorian takeover of Lorien.