The Sharon commuter rail station has been granted an extension on the deadline to make the station and its concession stand handicapped-accessible. The Architectural Access Board, a regulatory agency within the Executive Office of Public Safety and Security, granted a time variance Oct. 15, according to Terrel Harris, a spokesman for the safety office. The extension lasts until Oct. 1, 2013, and requires the Massachusetts Bay Transportation Authority to provide a temporary ramp at the concession stand within 30 days of receiving a written decision from the board. The decision was expected to be sent about three weeks after it was rendered. According to Harris, the MBTA was making improvements to the platform to help the disabled when the cost triggered a review, and the facility must now be brought up to code.