To further complicate this, the scenario you described you are the player getting the 7 ball, and your opponent made the 7.
In the Philly area where I'm from we usually played: call the spotted money ball only, 9 is wild for both players, and money ball spots on the break if made by either player, and if made by the spotted player it spots and he does not win. We almost never, ever, played wild spotted money ball.
Now, when playing this way, every ball is wild, except the spotted money ball. If you are the player getting the spot, shit in your money ball (and no other ball), you keep shooting, but you don't win, and your money ball stays down.
If you are the player giving the spot, you don't call ANY ball at any time. So if you have a chance to shit in your opponents money ball, by all means go for it if you want. You just increased your odds of winning by taking the spotted ball off the table. Under no circumstance is this called.
I moved to Atlanta 10 years ago, and now go to Philly for Xmas vacation. My last trip up, it was all new players. And they all play call every shot in 9 ball. I wanted to strangle them all. The game makes zero sense that way, especially when giving or getting spots. Its fukking stupid. End rant.
In contrast, playing in Atlanta, EVERTHING is wild in 9 ball, even the spotted money ball, and even on the break it counts as a win.