Hey y’all, Muirén here. I keep waiting to see K9 Mark IV regeneration, an upgrade based on, or inspired by the Boston Robotics dog-like Spot concept — not wearing a typical fursuit, but rather, cosplay better suited to Whoverse canon, and most important, motion-capture technology that enables an actor to bring K9 to life as never before, interacting in real-time with the Doctor(s) and Companion(s).
About K9 per the Doctor Who Wiki
First appearing with the Fourth Doctor in 1977, shortly after fighting a Rutan scout at Fang Rock Lighthouse, (TV: Horror of Fang Rock) the Doctor and Leela were joined by K9 Mk 1.
K9 has been a central character in three Doctor Who television spin-offs: K-9 and Company (1981), The Sarah Jane Adventures (2007–2011), and K9 (2009–2010). The character was created by Bob Baker and Dave Martin, to whom rights to the character still belong. Though never intended to be a recurring character, K9 was kept because he was expected to be popular with young people.
There have been at least 4 separate K9 units, with the first two being companions of the Fourth Doctor. Voice actor John Leeson provided the character’s voice, except during season 17 of Doctor Who, when David Brierley stepped in briefly.