Former “Who’s the Boss?” star Judith Light will return to ABC next season in “Phenom,” the latest comedy series from producer James L. Brooks’ Gracie Films.The series will feature Light as the mother of three kids, one ofwhom happens to be a precocious teenage tennis pro. Brooks, who will exec produce, is also working with Heide Perlman on a revamped version of “Sibs”– their first show for ABC under the company’s exclusive multi-series relationship with the network. “Phenom” will be produced in association with Columbia Pictures TV — which also made “Boss”– under Gracie’s overall movie and TV deal with the studio. “Who’s the Boss?” starred Light and Tony Danza and played on ABC from 1984 through last April, ranking in the top 10 four of its eight seasons and providing a springboard for launching several other successful series. Off-net success It also has the distinction of being the second-highest-grossing sitcom in the history of off-network syndication, behind only “The Cosby Show.” Shortly before “Boss” ended its run last spring, Light made a deal with Columbia to star in a CBS comedy, “Letting Go,” but the project — which would have featured Light as a romance novelist — failed to go forward. The “Phenom” deal, confirmed by Gracie, continues a long affiliation between Light and ABC that included five years on the web’s daytime soap “One Life to Live” before “Boss.” Light also headlined the telefilms “Wife, Mother, Murderer” and “The Ryan White Story.” She’ll also be seen Sunday in a CBS vidpic, “Men Don’t Tell,” opposite Peter Strauss.