First, you'll want to become a expert in your company's product domain. This will make your creative flashes much more relevant, and therefore more likely to see the light of day.
Second, start small. Use your own time to create a new tool which you know your team will find useful, and use the opportunity to teach yourself something new while you're at it. After a few successive wins you'll be allowed more and more leeway to apply your creative energies during company time, and the impact of your successes will grow.
Third, don't ask your manager for permission to work on Side Project X, at least not until you have somewhat of a reputation for delivering useful innovations. It truly is easier to beg for forgiveness than to ask for permission.
Lastly, give your colleagues a sense of ownership. People tend to be much more supportive of innovations that they feel they're a part of.
As someone almost as old as jblow who has worked across a wide gamut of different companies from very small to very large, this is sometimes true, but is by no means universal.
You would rationally think that if you are directly improving team productivity, customer satisfaction and the bottom-line that'll earn you more autonomy, but office politics are not always on the same continent as rationality.
You have to remember that if you're not the owner of a company, you have no rights to the products that company makes. Whatever privileges you have you keep by the grace of the owners, and when they change ...
Ofcourse, if you're the owner you're unlikely to actually be able to write code all the time, having to deal with the soft parts of the business. The grass is always greener on the other side I suppose.