Bill Fitch, 89, a twotime NBA coach of the year who guided Boston to one of its championships during a Hall of Fame coaching career spanning three decades, died Wednesday night in Lake Conroe, Texas, surrounded by family. Fitch coached for 25 seasons in the NBA, starting with the expansion Cleveland Cavaliers in 1970. He was Larry Bird’s first pro coach in 1979, won a title with the Celtics in 1981 and spent time with Houston, New Jersey and the Los Angeles Clippers.