Oct 6 (Reuters) - Canada’s main stock index opened lower on Wednesday as energy stocks tracked a retreat in oil prices, with sentiment dented further by worries around higher inflation. At 9:33 a.m. ET (13:33 GMT), the Toronto Stock Exchange’s S&P/TSX composite index was down 91.89 points, or 0.46%, at 20,091.54. (Reporting by Amal S in Bengaluru; editing by Uttaresh.V) Our Standards: The Thomson Reuters Trust Principles.