Both of the first two S9 episodes have referenced 'Classic Who' which I am liking. I'm not sure about Missy as The Master. And... Spoiler: plot point of S9:E2 ... if the Doctor was dying, wouldn't you think he'd leave his 'will' to somebody like River Pond instead of The Master? I mean, after all, not only is River his wife but she is also half-Gallifreyan. And, after all, he is a Time Lord, he could've left the will to any of those who have traveled with him over the years.