The events of 9/11 don’t turn bad strategies into good ones.
None of the failures that allowed 9/11 to happen had anything at all to do with being insufficiently engaged in military intervention abroad; nor has engaging in these interventions made us any safer. They have cost us trillions of dollars, thousands of lives, and tens of thousands of wounded - all numbers that continue to mount even as we lack the ability to articulate what exactly our military objectives are.
From what Osama Bin Laden has said, 911 attack was a retribution for US military presence in Muslim countries.