I had to do some digging on this as I'm not very familiar with both Kissmetrics and their integrations. However, I did find an article in their docs that mentions Shopify specifically.
It seems like Kissmetrics' primary method of integrating with Shopify is through an app the imports the data using our API. You could reach out to them for more information on this but it might require a custom implementation - a quick search of our App store didn't return any "off-the-shelf" solutions.
Hope this helps