’Tis the season for singing. Students in the Handel and Haydn Society’s vocal apprenticeship program wowed the crowd with their carols before the “Messiah’’ at Symphony Hall the other night. The youth choir attracts kids from every neighborhood of Boston as well as many of the suburbs. . . . The annual South Boston Holiday House tour to benefit the Laboure Center was a big hit. The crowd of visitors included Jacque Francona, wife of Sox skipper Terry Francona, SBLI honcho Bob Sheridan and wife Jean, UMass Boston chancellor Keith Motley, and former Senate president Billy Bulger and wife Mary.