The $8K you each got was an advance payment on the credit, subject to you both fulfilling all the requirements. One of them will have to be paid back. For a number of reasons. Previous comment addresses one of them, the home has to be owner occupied, so at least one of the homes doesn’t qualify. Also, on a joint return, both spouses have to qualify, and the 2nd purchase wouldn’t qualify for the new homeowner credit since your wife previously owned a home, even if just for a few months.

Since you both amended the previous years returns, the proper way to fix it would be to recapture the 2nd credit (assuming the 1st home is the one you’re now occupying) on your ’09 return. If you’re occupying the home purchased 2nd, it might get a little dicey. Since it qualified when you purchased it, I suspect the credit will stand and the 1st credit should be recaptured. Where it gets dicey is that the law says that both spouses have to qualify, since she previously owned a home, neither of you qualify. But since you weren’t married at the time of either purchase, you’re probably OK.

Or, you could ignore it on your ’09 return and see if they catch it. 25 years ago, that might have been a pretty good bet. The IRS had few mechanisms to follow that kind of stuff. But over the years, they’ve got much better at it. Penalties and interest would apply. Pretty high risk.