The two-disc boxset includes the final six episodes of the season - The Zygon Invasion, The Zygon Inversion, Sleep No More, Face the Raven, Heaven Sent and Hell Bent. Also included is a set of short behind the scenes videos documenting the making of the episodes.
The DVD and Blu-ray are currently priced at £32.80 and £50.07 respectively on Amazon, though this price will likely fall to about half of that soon.
Series 9: Part 2 will be released on 4th January 2016, with a complete Series 9 boxset presumably including the 2015 Christmas Special following later in 2016.
[Source: Doctor Who TV]