I'm assuming that the speed is speed of encoding rather than playback? This isn't something that many people are particularly worried about.
I think the 40% slower than vp8 was for playback. However, encoding speed also has to be reasonable, or there will be no content. With youtube, google may have a good head start if they succeed in getting others on board.
As your information is all taken from Google please take it with a huge pinch of salt. Google are bound to present a rosy view of VP9 in comparison with h265 given their investment in it.
Of course, but if the presented videos are any indication, it looks quite good. It doesn't have to be perfect. As long as it is significantly better than h.264 and close to h.265, it should find widespread use. Opus is also an excellent audio codec with very low latency, which will make this a good option for real time communications.
Personally I'm not keen on this. I don't care if its royalty free and unencumbered by patents. I don't want a single entity in control of a standard and regardless of the open nature of this Google are still in control. If this were Apple* or releasing a patent free codec to the world would you be so welcoming?
* Don't be dismissive of this Apple/NeXT do have a decent record of open source software releases.
Once the bitstream is frozen and the codec is open, you are free to use it as you like. The code is already available under a BSD-style license, though I do expect that a formal standard will be forthcoming. The availability of hardware should also provide incentive not to break compatibility in future versions.
I don't see how having the MPEG LA in control of any standard is a better option. The primary difference is that developers are free to incorporate this into applications without the trouble and cost of licensing. That directly benefits users, so perhaps you should care about royaltys and patents. The x.264 project is great, but it is limited in that respect.