Does click frequency account for relevance?
Depends on the user's intent, for starters. 

Users normally only view the first set of links, which means that unless the link is viewable, it's not getting clicks; meaning you'd have to be positive those are the best links, otherwise the clicks are most likely going to reflect placement, not relevance. For example, here's a click and attention distribution heat-map for  Google search results:



Further, using click frequency to account for relevance is not a direct measure of the resource's relevance. Also, using clicks is problematic, since issues like click-inflation, click-fraud, etc. will pop-up and are hard to counter. 

That said, if you're interested in using user interaction to model relevance, I would suggest you attempt to measure post-click engagement, not how users respond to search results; see "YouTube's head of engineering speaking about clicks vs engagement" for more information, though note that the size itself of the content is a factor too.

Might be worth noting that historically Google was known for PageRank algorithm though it's possible your intent is only to review click-streams, so I won't delve Google ranking factors; if you are interested in the Google's approach, you might find a review of Google's Search Quality Rating Guidelines.