 Bostwick started in Stevenage's first game of the 2009 – 10 season, in a 1 – 1 draw against Tamworth, and also provided the assist for Joel Byrom's goal in Stevenage's next home fixture against Ebbsfleet United. His first goal of the season came in the club's 2 – 1 home win against Rushden & Diamonds, scoring from the edge of the area to give Stevenage the lead. He also provided an assist in the club's 3 – 2 away fixture against Mansfield Town at Field Mill, as Stevenage came from two goals down to win the match. A week later, Bostwick scored a volley away at Chester City, although due to Chester City being expelled from the league, Bostwick's goal, and subsequently Stevenage's 1 – 0 win, were removed from the records. Bostwick continued his goalscoring form, scoring from 25-yards after a well-worked corner in injury time, in a 4 – 0 win against Hayes & Yeading. He scored a similar goal against Gateshead in November 2009, his fifth of the season. His next goal came in March 2010, scoring the opener from 30-yards against Crawley Town as Stevenage won 2 – 0, and he scored another goal two weeks later, heading in an Andy Drury corner as Stevenage came from behind to win 2 – 1 at Grays Athletic. Bostwick also played in the club's 2 – 0 win against Kidderminster Harriers at Aggborough in April 2010 – the game that secured Stevenage's place in the Football League for the first time in the club's history. He played in five of the club's FA Trophy fixtures during the 2009 – 10 season, scoring once in a game against Dover Athletic in January 2010. He also played in the Final at Wembley Stadium, but was unable to record a third Wembley victory as Stevenage lost 2 – 1 to Barrow after extra-time. In total, Bostwick played 52 matches in all competitions, scoring eight times. At the end of the season, Bostwick was out of contract and Westley announced that he expected him to leave, saying it would be "very difficult" to keep hold of him. However, in June 2010, Bostwick signed a new two-year deal with Stevenage, despite attracting interest from several League One clubs.
