The Romford-born forward scored ten goals at under-18 level last season and enjoyed a positive end to the 2024/25 season after netting eight goals in the Toon Teenagers' final nine Under-18 Premier League North fixtures.
Kacey made his full debut for the Magpies' U21s side during October's Premier League 2 visit of Tottenham Hotspur as well as scoring in the UEFA Youth League against FC Barcelona.
The 18-year-old committed his future to the Magpies after signing his first professional contract this summer and will link up with Robbie Stockdale's U21s squad this season.
After signing his maiden pro deal, Wooster told newcastleunited.com: "It's a good feeling to sign my first professional contract and a proud moment for me and my family but hopefully it's just the start of a good career.
"Newcastle had that belief in me when I signed from Southend at 15. Now, it's just repaying the favour and performing on the pitch."