[4] On July 24, 2021, it was announced Boone had returned to the United States and signed for USL Championship side San Diego Loyal.
[6] On January 27, 2022, Boone was announced as the third player to sign for USL Championship expansion side Monterey Bay FC.
[7] Boone was included in the starting 11 for Monterey Bay's inaugural match, a 4–2 loss to Phoenix Rising FC.
[8] Boone scored his first and second goals for the club during the first win in Monterey Bay FC history, a 3–2 victory over Oakland Roots SC.
[9] Boone finished the season with eight goals, tied for Monterey Bay's golden boot with teammate Sam Gleadle.