The feature that has me the most excited about Live 9 is Drum and Melody to MIDI. I’ve use various other tools to do this (Melodyne for one) but it’s always been hit or miss. It does look like Ableton has cracked this and it’s going to be an amazing and useful tool.
“Your voice is the new keyboard: sing, beatbox, tap a rhythm on your desk, or play any solo instrument to capture your musical ideas as they come. Then use the Melody- or Drums-to-MIDI feature to turn your recordings into MIDI clips that you can edit and reuse with any sound.” – ableton.com
For more info: ableton.com/en/live/new-in-9/