This is canon
At the former Outpost Gallifrey Doctor Who forum a question was asked about what fans consider as canon and there was a poll and the list to choose from included the TV shows, books, audios etc.
There was one option of K9 and Sarah stories. This option was about all the stories that Sarah and K9 had appeared in regardless of media. This was not right as there should have been a seperate option for K9 and Company and another for non-TV appearances featuring the two characters.
One person Paul Castle had trouble comprehending my argument saying that is no way to cover all the variables. Mr Castle simply does not get it. K-9 and Company was made for television and therefore should automatically consider as canon while the canoncity of non-TV appearances featuring Sarah and K9 is a matter of the individual. It is as simple as that and baffled why Paul Castle could not understand this.