There are plenty of opportunities to work as a freelance software developer. There are lots of contract software development opportunities available. Just look at one of the contract hiring boards, like dice.com or craigslist, to get a feel for the variety of assignments out there. It is a bit of work to break into this field: once you have some projects under your belt and a track record of success, it's easier to get more work. It might make sense for you to work as a salaried employee for a few years to get some experience.
It's also helpful to pitch yourself as a specialist in something people need. So-called "line of business" web applications (custom applications for particular business purposes) can be an excellent way to position yourself.
"Computer scientist" in the working world usually refers to a university professor or member of technical staff in a research organization. Many computer scientists have PhD degrees and are motivated by pushing the boundaries of knowledge. That sounds hard to do on a freelance basis without at least a few years in an university or research lab.