WRENTHAM - State Sen. Scott Brown today said he is “about 90 percent” sure he will run for the late Sen. Edward Kennedy’s seat, and outlined a campaign strategy designed to play down his GOP credentials. Brown’s entrance would make him the second and most well-known Republican in the race. GOP Canton selectman Robert Barr announced yesterday he will seek the seat. The Democratic field is filling as well. Yesterday's announcement that former U.S. Rep. Joseph Kennedy, the late senator’s nephew, would not run was expected to draw in additional Democrats. Brown said he will likely announce Thursday, or Friday...