If the phrase "IN GOD WE TRUST" were ruled to be unConstitutional, not only would we have to retool the dies used to press coins, all U.S. currency in circulation (I think this might also include all government backed securities too) would have to be recalled and replaced with the Court approved equivalent.

Of course, we could just worry about the currency that will be pressed and say they currency already in circulation is ok. But that would be too pragmatic for the 9th Circut and would also dilute the weight of their ruling. Paper money can last for decades, coins forever. If it's ok to let it go on old money, why not just acknowledge that the issue is not worth the bother. There are bigger fish to fry.