Sept 7 (Reuters) - Canada’s main stock index rose on Tuesday, tracking a rise in global stock markets, as investors bet on central banks sticking to a loose monetary policy against the backdrop of a slowdown in the post-pandemic economic rebound. * At 9:31 a.m. ET (13:31 GMT), the Toronto Stock Exchange’s S&P/TSX composite index was up 55.94 points, or 0.27%, at 20,877.37. (Reporting by Amal S in Bengaluru) Our Standards: The Thomson Reuters Trust Principles.