Tower Hill (13-2, 7-1) tied for the title in 2005 and '08.
"It was a huge momentum boost for us and you could hear the emotion from the bench," Tower Hill coach Brad du Pont said. "It was a smart, heads-up play. It was also one of those 'no-no-no-yes-yes-yes' type of goals. Great play. It was a huge play and wound up being a turning point."
Tatnall's Joe Fragomele scored 17 seconds into the third quarter to cut the Hillers' lead to 6-4.
Less than two minutes later, Hobbs intercepted a pass at midfield, ran five yards and then fired a 45-foot shot into an empty net. Tatnall goalie Bobby Schluter had moved the ball upfield and didn't have a chance to get back after Hobbs got control of the ball.
For Hobbs, it was his first career goal.
"I was very happy," Hobbs said. "It was awesome. I picked up the ball and heard the crowd. I looked up and saw the goal was open. It was really an awesome feeling. It feels great right now and I'm sure it will carry into the weekend."
Tower Hill extended its lead to 9-4 with 4:35 remaining on a pair of goals by Chas Robino.
Austin Beer, who led the Hornets with three goals, scored twice in the final 3:14 to close within 9-6. His third goal came with 1:40 left, but they wouldn't score again.
The Hillers outshot Tatnall 28-25. Evan DeDominicis paced Tower Hill with three goals while Ripley Nielsen added two goals and an assist.
Tower Hill goalie DeMetrius Murray made 13 saves and kept the game close in the early stages with eight stops in the first quarter.
It all added up to a conference championship.
"Winning the conference outright was one of our goals this year," du Pont said. "We had a slow start at 1-2. The kids didn't lose heart and continued to get better and better. It's tough playing in this conference when you see everyone twice. There are no secrets. You have to play well."
Tatnall, which fell to 7-6 and 6-2 in the league, last won an outright conference title in 2006."I told the kids not to hang their heads because we've got two tough games coming up and hopefully a postseason," Tatnall coach Peter Duncan said. "It wasn't meant to be on this night. We'll learn from it and move forward as a group."