As with Torchwood, there are two major categories for K9. There's category:K9, which is about the character. Then there's category:K9 (TV series), which is about the 2009 television show. Choose wisely.
So why is it K9 and not K-9? Because this evidently the original form of the name, and also the way used most often in print. It's important for wiki functionality that we choose one way of spelling it, and stick to it. Interested in reading more? Is it even possible that you could be? If so, read this background note
K9 literally required a global financing deal. It is one of the many subjects we deal with on this wiki that have practically no involvement by the British Broadcasting Corporation, and arguably one of the most notable. Heck, they didn't even exhibit it in the United Kingdom. The essential rights to the series are held by Metal Mutt Productions.
Unlike The Sarah Jane Adventures, which really didn't have any overt romance for its younger characters until the last couple of episodes, K9 almost immediately suggested a love triangle between its three stars. Then, as the season progressed, the question of whether Jorjie would end up with Starkey or Darius became more urgent. We never quite found out, but at least we got a kiss here and there.