Sept 22 (Reuters) - Canada’s main stock index opened higher on Wednesday, as energy stocks climbed more than 2%, with investors focused on the U.S. Federal Reserve’s policy decision due later in the day. At 9:31 a.m. ET (1331 GMT), the Toronto Stock Exchange’s S&P/TSX composite index was up 156.76 points, or 0.77%, at 20,401.05.