The plugin does not sit in memory or intercept any options. It changes the db directly (dangerous, but powerful). Once a change is made, it is permanent so you can deactivate the plugin until it is needed again.
This plugin, like most of the ones that I write, I did for myself after reading an article on plugin development. I realized that when I used an option in WordPress, I was letting the option be "autoloaded", even the options that were used only occasionally. This loads the options on every page load of WordPress, whether they are needed or not. Several of my very early plugins did not clean up after themselves when deleted.
I inspected the database and found that it was full of orphan options from plugins that I had tested, and almost every option was autoloaded. Fixing by hand was a pain so I wrote a small plugin to help me.
After running the Options Optimizer on a dozen sites, I decided that it might be useful to others so I cleaned it up to make it presentable, suppressed the WordPress default options, and I wrote the readme file.
I hope that everyone finds it useful, and that I get lots of suggestions for improvement.