After you use the bend will shout (full charge), you should be able to get on him.
Has the arrow on his head and is "ready to ride". Lvl 93 character... abandoning game since I don't have a save from before I tamed him and died during. Just sits there, unmountable.
Console or PC?
If PC you can just ... advance the quest by brute force and TCL to walk to Miraak