The president has extremely broad powers. In general I think it safe to assume he can do these things (sans demanding a cut of the proceeds). Typically these powers are granted during emergencies, but again, the president seems to be able to declare those whenever he wants.

It's just before now they were wielded with restraint and mostly ignored. This should be a wake up call.

Part of the issue is there is now a real discussion over whether or not this is allowed. In a previous United States that this discussion would have existed would have been ludicrous. The basic premise of the IEEPA seems valid, but there seems to be very little effective check by congress.