Remix - 9V battery safety cover
I added rings of a slightly larger diameter to ecodad's clips so they retained better, like if you wanted to transport them. Also, I added a tab to help removal in case they get stuck. Then I put a couple small holes in one so you can test them with stabby probes without removing the cover -- only something really small can get in there, so risk of shorting is only marginally increased, if at all.
And, thanks to ecodad for saving his thing in .123dx and sharing!
Update: I put a ring on the small (-) post so it snaps in, too. Also, I've widened the test holes to allow a 2mm meter probe and beefed up the small post, as I had one snap off. Also, I posted all four versions as .stl files (9Vcover*.stl) in addition to the edited .123dx file.
Upgrade! :-)