If the Founders' intent was to for the Executive to be able wage his own wars, why would that excerpt from Article 1, Section 8 be necessary?
As I've said, I'm not a legal expert, but I do know that the Founding Fathers wasted no words or ideas as far as the Constitution is concerned. If they said it, it meant something. Conversely, that fact that something was not said meant something too.
It's only lawyers that try to read between the lines that screw things up.