April 28 (Reuters) - Canada’s main stock index opened higher on Wednesday, supported by higher oil prices and upbeat February retail sales data, even as investors awaited the outcome of the U.S. Federal Reserve policy meet. * At 09:31 a.m. ET (1331 GMT), the Toronto Stock Exchange’s S&P/TSX composite index was up 49.64 points, or 0.26%, at 19,224.73. (Reporting by Devik Jain in Bengaluru, Editing by Sherry Jacob-Phillips)