I think you've got the right idea, but the wrong event. The entire nation pulled together in the days after 9/11, and GWB acquired their support with the speech he gave about a week after 9/11. Recall the comment that followed by Pat Buchanan: "Tonight, George Bush became President".
"These terrorists kill not merely to end lives, but to disrupt and end a way of life. With every atrocity, they hope that America grows fearful, retreating from the world and forsaking our friends. They stand against us, because we stand in their way."
"We are not deceived by their pretenses to piety. We have seen their kind before. They are the heirs of all the murderous ideologies of the 20th century. By sacrificing human life to serve their radical visions - by abandoning every value except the will to power - they follow in the path of fascism, and Nazism, and totalitarianism. And they will follow that path all the way, to where it ends: in history's unmarked grave of discarded lies."
http://www.guardian.co.uk/world/2001/sep/21/september11.usa13
Bush’s first comments to the nation on the day of 9-11 were viewed as “shaky,” as if he weren’t quite in command of the situation or how to respond.
The Ground Zero remarks with firefighters were on 9-14.
http://www.americanrhetoric.com/speeches/gwbush911groundzerobullhorn.htm
Bush seem much more in command while also exhibiting the kind of empathy that apparently Americans had come to expect from a president under Bill Clinton. I think the key was this was a largely unscripted moment in which Americans saw their president as both a “man of the people” who understood and really felt the loss of the families affected by 9-11, but also as a tough no-nonsense commander in chief who was resolved to strike back at the perpetrators as opposed to getting the UN to pass a resolution of protest against the attack. People could see he was speaking from the heart—not reading from a canned speech or teleprompter. The crowd reaction said it all.
I concur his subsequent Oval Office speech likewise carried through on this “strong but compassionate” leader theme. But I’m reasonably certain I’m not alone in believing 9/14 was the first day this view of Bush had begun to emerge.