I suspect that if Reagan had just started his first term when 9/11 happened, we would have been in and out of Afghanistan before the end of his second term. Its had to say whether he would have messed with Iraq but if he did, it would have been long since over.
I certainly don’t think we would be playing games with Pakistan and its unlikely that we would have had any involvement in Libya.
Bush had withdrawn most of the troops from Afghanistan, it was winding down, waiting for Iraq to stabilize. It was Obama who insisted that Afghanistan was the “right war” and instituted the surge in Afghanistan.