The ship would be allowed to dock regardless of what Trump decided. Just Because Trump gives permission doesn't mean Russia needs permission from the US. If the US boarded the Anatolky Kolodkin, that would be an act of war against Russia. That exactly why the Cuban Missile Crisis was so tense: if the US did stop Soviet ships bound for Cuba then that would be an act of war against the USSR.

You might be right. Maybe Russia could actually deliver some more oil if they wished to.