Retribution: Bin Laden viewed 9/11 as a justified response to US policies in the Muslim world. In his view, the US had been waging a war against Islam, and 9/11 was a way of retaliating against this.
Inspiration: Bin Laden hoped that the 9/11 attacks would inspire other Muslims to take up arms against the US and its allies. He believed that the attacks would be a catalyst for a global Islamic revolution.
Provocation: Bin Laden wanted to goad the US into a wider conflict. He believed that the attacks would lead the US to take military action against Muslim countries, which would in turn radicalise more Muslims and create more support for al-Qaeda.
Victory: Ultimately, Bin Laden believed that the 9/11 attacks were a victory for al-Qaeda and the global jihadist movement. He saw the attacks as a way of bringing the US to its knees and ultimately destroying it.
However, it is worth noting that this information is based on Bin Laden's own statements and propaganda. Some analysts have argued that his motives were more complex and nuanced than this, and that he did not necessarily see the attacks as a simple act of revenge.