The winger, who spent time at Arsenal, Fulham and Crystal Palace as a youngster, is eligible to play today against Welling United.
Cadogan has been without a club since the end of last season, after becoming one of 13 players to be made redundant by Aldershot Town due to their administration.
Last season he made 28 appearances for the Shots, 25 of which were starts, scoring one goal and topping their assist chart.
The 23-year-old graduated through the Palace youth system before going on to make 23 first-team league appearances.
He has also spent time on loan with Burton Albion and Rotherham United.
Good luck Kieron!