Reseves can occupy and number. However the number 16 jersey is usually occupied by a player in the front row, more commonly by a hooker
He plays as a reserve and comes off the bench.
In Rugby Union (15 a-side, as opposed to Rugby League which is 13 a-side), the number 9 shirt is worn by the scrum-half
I believe it was number 7
15
Benji Marshall is known for wearing the jersey number 6, which is typically associated with the five-eighth position in rugby league. Throughout his career, he has predominantly played for the Wests Tigers in the NRL, where he built his reputation as a standout playmaker. His number 6 jersey has become iconic among fans of the sport.
Usually number 8
A player with 12 on their jersey in the Union code will play inside centre in the backs line (stands with another centre outside them and a flyhalf the other side)
Hes an open side flanker number 7
Number 22 in rugby is a player on the reserves. Therefore it could be occupied by a player of any specialised position. However, the player in number 22 is usually an outside back utility(playing centre, wing and fullback)
Lee Halfpenny wears the number 15 shirt for the Wales national rugby team. He is known for his skills as a fullback and has been a key player for Wales in various international competitions. His jersey number reflects his position as he plays primarily in the backline.
The number is normally associated with the players playing position
A Rugby jersey.