NEW YORK, Aug 28 (Reuters) - Wall Street headed higher and crude prices jumped on Monday, at the outset of a week marked by light volume and heavy economic data, boosted by mounting hopes that the Federal Reserve will take a rate-hike breather in September. "In remarks delivered at the central bank conference in Jackson Hole, Wyoming, Fed Chair Jerome Powell had on Friday said inflation was still too high, but noted that economic uncertainty called for "agile" monetary policy making and that the Fed would proceed "carefully". See here for a complete list of exchanges and delays