Lets put some context on this data:

At a local club paddle a few years ago, a bunch of old weekend warrior paddlers all paddled my Petrel Play 14' long kayak as fast as they could and measured the results with a GPS. Everyone was able to get this short, not particularly fast kayak up to between 8 and 9 mph.

Greg Barton set the course record at the Blackburn Challenge for a kayak with an average speed of 7.74 mph average speed over a course of almost 20 miles

In the Molokai Challenge winners complete the 32 mile course with an average speed around 9.5 mph. This is an extremely rough crossing.

The current record holder in 200m sprint kayak has an average speed of 13.19 mph

My best GPS measure speed on flat water was 11 mph in my Mystery design. I'm not that fit, that speed doesn't last long.

My best GPS measured speed over distance was an average of 12 mph over a 1/4 mile in my 17' long Petrel surfing a wave about 10 inch tall.

My top GPS speed was 21 mph surfing a 5 foot wave.

I would rate my performance as typical of a strong sea kayaker.

In that context, 9mph is not very noteworthy. I am certain that there are traditional Aleut (iqyax/kayak/bidarka) designs (such as the MAE 593-76) which could handily exceed that speed with someone like Greg Barton paddling it or even me for that matter. And given a nice down wind run and a following sea they would move along at a good clip similar to a surf ski.

Nova is entertainment and they did a good job making an interesting TV show about a subject that interests us all, but in the interest of drama they overstated the significance of the bidarka performance. And, of course a kayak designed to be paddled in the sea has better rough water performance than a sprint kayak that can get swamped in 6" waves. This is not news to anyone knowledgable in kayaks. Comparing these boats is apples and oranges.