A sampling of this month’s Irish/Celtic music-related events in, or slightly beyond, Greater Boston.•The Burren Backroom series begins this month with an appearance by The Alt (Nuala Kennedy, John Doyle, and Eamon O’Leary) on Sept. 7 at 7:30 p.m. Click here to read an interview with Kennedy.On Sept. 11 at 3:30 p.m., the series will present a special collaboration featuring