If 09 is the month (September), 17 is the day, 11 is the year, that would be September 17, 2011. That seems plausible. So the first part is the date 09/17/11.
Then the next number is -809. That could be a sequence number or an identifier. Maybe it's the part of a series or a specific identifier for this particular file or version. 091711-809-carib-whole.wmv
Need to avoid assuming too much about the video's content. Focus on the given filename and its plausible components, then provide a general overview of the Caribbean as it might relate to the video topic. Make the write-up educational and informative, covering geography, culture, history, tourism, etc., relevant to the Caribbean as a tourist destination, cultural region, political entity, etc. If 09 is the month (September), 17 is
Alternatively, maybe "carib" refers to a specific project, organization, or code-name. However, without more context, it's safer to assume the Caribbean. The user might be expecting a detailed article on the Caribbean that the video might cover. Then the next number is -809