This is much ado about nothing.
The grand jury could return a recommendation of a murder indictment against the president, yet no law enforcement officer in America could do anything to promulgate it.
The only course of action to "try" a sitting president is in the Senate as prescribed by The Constitution: a trial of impeachment.
And that trial cannot begin until articles of impeachment have been returned by the House of Representatives. And this, folks, simply ain't gonna happen.
Of course no one's going to listen to me, but if they did, I'd recommend to Mr. Trump that he fire Mueller immediately, then take the heat until it subsided. What did that ol' guy Truman have to say about that?