At the moment, there is no way to do this. As given, it will link through to the DOI resolver. One potential solution is to find an alternate reference -- so, getting the PDF into arXiv for instance would then work. In this case, I will ask the authors to see if they will do this, but it doesn't solve your short term problem.
I fear in this case, the quickest solution will be to put the link in separately. So
[cite]10.1021/jf904082b[/cite](pdf)
would like fine.
This is a good use case, however, and I should allow authors to point to somewhere different. I will add this to the next version of kcite.