Let me begin this firmly: Do Not Try This At Home...unless, that is, you think you can trust an amateur electrician who goes by Afroman, and is a fan of Little Mermaid fruit snacks.
That being said, Afroman has definitely put together a system that will recharge a regular 'disposable' alkaline 9 volt battery. Basically, Afroman used a very small charging current (65 mA) and found that he could recharge the 9 volt Duracell overnight. And while we at TreeHugger have known this is possible for some time, Afroman did it for about 50 cents in parts from Radio Shack.Now, this means that he left the 9 volt Duracell charging in his house while he slept without monitoring the stored voltage in the battery. This could have, of course led to loss of property, injury and death, but, nonetheless, he did it.
This begs the question, if Afroman can do it, why doesn't everybody? Maybe there's a good reason, I hope so anyway, because it'd be a shame if all of those batteries ended up in the landfill because 'disposable' is better for business.