The Catamounts (12-6, 5-1) have a half-game edge over Albany and the Seawolves (13-5, 4-1), whom they defeated in last season's conference tournament final.
Rusin scored eight points during a 12-0 run early in the second half that gave Vermont a 44-29 advantage.
Stony Brook, after trailing by as many as 18 points, got to within four, 65-61 with 2:48 left, after a dunk by Tommy Brenton. But Sandro Carissimo responded with a layup and two free throws on Vermont's next two possessions for an eight-point lead.
Brian Voelkel had six assists for Vermont, giving him 405 for his career.
Mike Brey is looking at former Notre Dame players to fill two assistant jobs that have opened up with the departures of Martin Ingelsby and Anthony Solomon.
Purdue's 2016-17 prospects got a jolt Wednesday when forward Caleb Swanigan announced he will return for his sophomore season.
Clemson's Jaron Blossomgame says he is withdrawing from the NBA draft and returning to school for a final season.