Complex sentence: The Browns'6-3 record is the franchise's best 9-game start since returning to the league in 1999, and their best start since the 1994 season when the Browns opened the season with a 7-2 record.
Split into simpler sentences: The Browns'6-3 record represented the franchise's best 9-game start since returning to the league in 1999. It was also their best start since the 1994 season when the Browns opened the season with a 7-2 record.