Judging by Porters actions, he either exceeded them greatly in his efforts to antagonize the Confederates (shooting at their ships) or we haven’t seen all of his orders.
IMO Porter’s actions at Pensacola are driven by Porter’s ambitions. If he had “secret” orders from the President of the United States, he would have not been the least bit reluctant to show them to Meigs when he was prevented from entering Pensacola harbor.
Orders to deliberately start a war? Wouldn't the military men of that time been duty bound to not only object, but to let it be known the President was deliberately starting a war?
Your argument does not dispel the notion that Porter was acting on confidential orders to trigger a war.