No. Even if section 4 is interpreted as meaning that the the debts of the United States have first claim to Federal funds, all that would allow Obama to do (indeed he would be Constitutionally obligated to do this if that is how it is interpreted) would be to impound other appropriations and spend them on the public debt instead. In no event could section 4 be interpreted as the President has authority to incur debt not authorized by law above the debt ceiling set by law to pay interest on the existing debt.
So that could mean that Obama can impound funds appropriated for Utah, Alabama, Alaska, Louisiana, and other red states to pay the debt.