The 21-year-old New Zealander signed for Stellies from Australian A-League Wellington Phoenix in August 2025.
He was largely used as a back-up keeper in the club’s DStv Diski Challenge side.
The former Roda JC player is reported to hae signed a three-year deal with the Buccaneers.
The player's representatives posted the announcement, saying: "Chapter for our client @dub_bn19 joining the @officialpsl_za champions @orlandopirates.
"Thank you to @stellenbosch_fc for the professionalism and role in Dublin's development thus far. The best is yet to come."
Boon arrives at Pirates following the exit of 28-year-old former Jomo Cosmos and TS Galaxy shotstopper Melusi Buthelezi.
Stellenbosch head coach Gavin Hunt has likened teenage sensation Quwan Plaatjies to former Bafana Bafana striker Mark Williams after the youngster announced himself in spectacular fashion with a hat-trick on his senior debut.
Orlando Pirates Reserves have embarked on a nine-day European Winners Tour in the Netherlands, with the reigning DStv Diski Challenge (DDC) champions set to face the country's leading youth academies.
Orlando Pirates will look to return to winning ways and keep pace in the Betway Premiership title race when they face Chippa United at Kings Park Stadium on Sunday.
Quwan Plaatjies marked his Betway Premiership top-flight debut with a hat-trick for Stellenbosch in their impressive 3-1 win over Marumo Gallants at Athlone Stadium on Friday night.
