Sept 8 (Reuters) - Canada’s main stock index slipped on Wednesday as investors stayed away from making risky bets ahead of the Bank of Canada’s interest rate decision later in the day. * At 9:31 a.m. ET (13:31 GMT), the Toronto Stock Exchange’s S&P/TSX composite index was down 19.53 points, or 0.09%, at 20,787.1. (Reporting by Amal S in Bengaluru; Editing by Arun Koyyur) Our Standards: The Thomson Reuters Trust Principles.