AFAIK he hasn't said anything in favor or against it yet, I am sure he is well aware of it but doesn't wants to clear his stance on this as it may go against him.
If he becomes president I think hes more likely to ban it if not declare war on it because you know... only terrorists and criminals use it.
Yes, he most likely will be against it.
There is not much to worry about as he will not be the next president of the U.S. Trump is nothing more than a clown. If he indeed turns out to be the next president, I think you will be right when it comes to him banning Bitcoin usage at any form throughout the entire nation.