In the 2008–09 season, McNabb played in the style of a defensive-focused defenceman, and his numbers reflected it. In 67 games played, he had 10 goals and 26 assists for 36 points, and also accumulated 140 penalty minutes. He also contributed in the playoffs yet again with five assists in four games. In that season, he played in the CHL Top Prospects Game for Team Orr, adding three assists for the squad and going +3 while doing so. He was also a member of Team Canada for the 2009 IIHF World U18 Championships., and the 2008 Ivan Hlinka Memorial, in which he and his team received a gold medal.