[citation needed] September made his professional debut in In the Heights, playing the role of Sonny.

[4] The show started its run at the Southwark Playhouse and September joined for its transfer to the Kings Cross Theatre in 2015.

[5] Original cast included David Bedella as Kevin Rosario, Eve Polycarpou as Abuela Claudia, Victoria Hamilton-Barritt as Daniela and Sam Mackay as Usnavi.

[6] He was part of the ensemble in the summer production of Jesus Christ Superstar at the Open Air Theatre in 2017.

[8] The production followed a successful concert run of the show with Jeremy Jordan as Clyde and Frances Mayli McCann as Bonnie in 2022.