On April 2, 2009, Bennett's former teammate at Vanderbilt during the 2005 season, Pro Bowl quarterback Jay Cutler was acquired by the Bears via a trade with the Denver Broncos.

Bears head coach Lovie Smith said Bennett would be given "every opportunity" to win a spot as a starting receiver alongside Devin Hester in 2009.

Bennett did just that during the course of mandatory mini-camp and training camp, as he showed an ability to make tough grabs in traffic and a willingness to go over the middle.

Bennett got off to a strong start in season in the Week 1 match-up against the Green Bay Packers, making seven catches for 66 yards.

A week later against the Detroit Lions, Bennett returned four punts for a 15-yard average and a long of 25 yards in place of an injured Devin Hester.

In Week 16 against the division rival Minnesota Vikings, Bennett caught three passes for 35 yards, along with his second career receiving touchdown.

Bennett caught his first career touchdown from Jay Cutler against the St. Louis Rams in Week 13 as well completing a career-long 71-yard pass reception.

During Week 6 against the Seahawks, Bennett laid a devastating block on Seattle punter Jon Ryan, allowing teammate Devin Hester to return his second punt of the season for a touchdown.

During the NFC Championship game, with Chicago trailing 21–7, Caleb Hanie, who was playing for an injured Jay Cutler, lofted a pass toward the left sideline to Bennett, who made Nick Collins whiff on the tackle and then raced untouched into the endzone for a 35-yard touchdown, but Green Bay still won the game 21–14.