Would have been 0; he’s CinC till noon....
What has happened in previous transitions?
Did the Guard commander, and others that would transition out, stay till the end of the day?
Did the incoming folks start at noon or earlier to overlap?
(Don tin foil hat.) Perhaps he told Obama that he would not allow his troops to be used in Obama's allies' plans to make the inauguration into a circus. The timing of this may be because the plan is to change commanders at a critical time, causing chaos and then blaming it on Trump. After all, the general was relieved when Trump was sworn in, right? And, he is black, so a racist Trump relieved a black general as soon as he was sworn in. Never mind the facts, the press will send out that story.