Kyle Shanahan has been around pro football for his whole life, he was around superbowl winning teams in his formitive years, has been coaching in the NFL for 9 years already and is 33 (which means he plays/ has played MADDEN FOOTBALL, which is a huge learning tool for game management) and has learned firsthand from a very good coach.
IMO, Shanahan WILL be a HC in the NFL very soon, why not now? The first season is almost always a wash, no matter who is coaching due to lack of knowledge of the talents of his players, so I say hire the young coach who has been around the game his entire life, and IMO is the very best candidate for this young teams future.