Doctor Who Series 9 What we Know: May 2015

Anything in italics is speculation only. Some have good evidence to be true but have not been confirmed by the BBC.

Main Cast

The Doctor - Peter Capaldi (full series)
Clara Osworld - Jenna Coleman (full series)
Missy - Michelle Gomez (Episode 1-2)
Kate Stewart - Jenna Redgreave (Episode 1-2, 7-8)
Osgood - Ingrid Oliver (Episode 7-8), still dead but this story will be seen before the event of Dark Water                  and Death in Heaven
Orson Pink - Samuel Anderson
Ohila - Clare Higgins (Episode 1-2)
Shadow Architect - Kelly Hunter (Episode 1-2)

Enemies

Missy - Michelle Gomez (Episode 1-2)
Zygons (Episode 7 and 8)
Ghosts (Episode 3 and 4)
New Monster (Episode 5 and 6)
Daleks (TBD)
Davros (Episode 1 and 2)

Episodes 

Episode 1/2: The Magician's apprentice/Witch's Familiar - Steven Moaffat
Episode 3/4: TBD - Toby Whitehouse
Episode 5/6: The Girl who Died/The Woman who Lived - Jamie Mathieson and Steven Moaffat/Catherine                       Teganna
Episode 7/8: TBD - Peter Harness
Episode 11/12: TBD - Steven Moaffat