Trailing sluggish box office results after its late March opening, the Robert De Niro-Ellen Barkin pic “This Boy’s Life,” which also starred Leonardo di Caprio, is coming to video Sept. 1, Warner Home Video announced Monday.The R-rated pic will be shipped in VHS and Beta, including a Spanish subtitled version. Neither has a price tag yet. The letterboxed laserdisc version retails for $ 34.98. The Michael Caton-Jones-helmed story about an overpowering stepfather first opened small, but stumbled by going wide. It has grossed $ 4.1 million to date.