On 17 September 2021, Bennison made his professional debut, scoring a try in St Helens' 26–14 loss to Salford.

[3] On 24 September 2022, Bennison scored a try during St Helens 2022 Super League Grand Final victory over Leeds.

[4] Bennison played 19 games for St Helens in the 2023 Super League season as the club finished third on the table.

[5] Bennison played 15 matches for St Helens in the 2024 Super League season as the club finished sixth on the table.

He played in St Helens golden point extra-time playoff loss against Warrington.