What you need is a switching power supply made to output 9V. You can build it yourself from parts, but it is tricky because electrical noise is a HUGE issue. You probably need to build in on copper-clad board which can be a pain, but I have done it before, and it can be done. I will try to dig up that schematic, as I think it was also meant to do 5V to 9V.
That said, if you can find one, this is one thing I would buy because it is a pain to build and there are a lot of details that make the design better that only people who do this kind of thing for a living get right. To get an idea of what you would have to build take a look here module.ro