Certificate program local community college...

...would this be worthwhile or should I stick to independent study. I have a degree in Engineering, but it's not in Computer Sciences. I'm thinking this could be of help if I consider to make a career change in the future.

certificate in C++

I rarely consider taking classes a bad idea, regardless of whether you get a certificate or ever use the knowledge/skills professionally. That's especially true if community colleges are as cheap and good in Illinois as they are here in California. The usefulness of the cert is somewhat dependent on the job you apply for. Some places like that stuff, some don't care. Whether it's worthwhile also depends on how likely this career change is and how soon you want to change. Any other programming experience you can put on your resume usually go a long way, especially directly related work experience, freelance or personal projects you can show off, or significant contribution to an open source project. Out of curiosity, what's your degree in, what's your current job and when/why do you want to change? Have you thought about what type of C++ job you would want?

I don't know that "certificate" is necessarily going to open any doors (certainly less doors than even an AS or AAS would), although the key word I suppose is "community" -- if that CC has a good rep locally, then that generally means that something worthwhile is happening; but it's probably not going to get you much outside the community. Following the link and looking at the classes, you've got two "find the power button" courses, a database course, two programming courses, and then that last class is apparently Windows programming by the course description, so that's not all bad. If you're curious you can always ask for the placement rates for recent grads.

"That's especially true if community colleges are as cheap and good in Illinois as they are here in California. "
>>>They are reasonable, and decent. The one I linked I've taken AutoCAD courses there. Top notch CAD dept. AutoDesk accredited.

"Out of curiosity, what's your degree in, what's your current job and when/why do you want to change? Have you thought about what type of C++ job you would want? "
>>>Mechanical Engineering (BSME) (Never really made it in engineering for whatever reason.)
>>>I work as a CAD Designer. 12 years+ (AutoCAD, SolidWorks, etc.)
>>>I just feel like I'm going stale in my current position. I'd like to try something new.
>>>Well most reasonable use would be in the CAD field (just when I try to get out, they pull me back in), but what I'd think I'd like to do is develop windows applications. I'm interested in learning GUI programming at some point.
>>>This is all down the road. I don't want to half-ass this. For now it's a hobby which I hope can develop into a profession.