The quip about atheists “dealing” aside, I think DrLizardo comments were encouraging: I would call him a model religious person for a pluralistic liberal society such as ours. (NOTE: “liberal” here is being used in the political theory sense of a society that sees itself as promoting individual freedom and social democracy.) That is, I appreciate Dr.L’s understanding that the private sphere is the proper place for his religious devotion and that imposing religious dogmas in public schools inflames people without necessarily doing anything important for religion.
I’d like to go a step further and say why I really disagree with “In God We Trust” both personally and philosophically. It’s not that I faint at the mere mention of God. Lots of people I deal with on a day-to-day basis are religious and I seldom have a problem with the way that God may figure for them in their assumptions or their speeches. I’m even occasionally said something like, “Thank God,” in a casual kind of way even though I hold no belief in an anthropomorphized divine being–which is usually what is meant by God in a monotheistic religious culture.
Although I am probably best described as an atheist, I actually consider myself a fairly spiritual person. And most of that spirituality I’ve cultivated from years of experiencing life in what I like to think is an open-minded way: for me the most contemplative experiences tend to come via human inventions such as philosophy, music, and even good movies, as well as the kind of conversations I can have with other people about these things. I guess that makes me a humanist, and brings me in line with the secular humanist tradition which arose exactly around the time that people began to feel less sure about God, but, at the same time, more excited about the human potential for discovering things. But for other people I think the same contemplative feelings can come from nature, or from non-humanistic philosophies such as those one finds in non-Western traditions like Buddhism.
What is nice for me about this open-ended approach to spirituality is that it gives me a lot of opportunities to find things in common with other people, including people who value mainstream religious beliefs.
Therefore what pisses me off about the “In God We Trust” mentality is how close-minded and dogmatic it is. It’s an insult to human variety and human potential.
The truth is that even the very religious suffer crises of doubt and pain: why should such very human questioning be covered over with a slogan–and in a classroom no less?
And the truth is that people in America, including Kentucky, are brought up to trust in all kinds of things: we trust in antibiotics; we trust in the FDIC to protect our savings; depending on who we are we may trust in our mother or father as the one person who loves us no matter what; or we may trust in CNN; or we may trust that Neil Young is the best guitarist that ever was; or we may trust that the weather report won’t let us down as we get dressed in the morning.
The interesting thing when you’re in a classroom–(I speak as someone who spends a lot of time teaching)–is figuring out how and why it is that people come to believe in such things; and how (or if) people can learn to believe in and trust each other. When you begin to think about it, trust is one of the most complex human attitudes anyone can possibly think of.
“In God We Trust” doesn’t ask us to think, to ponder, to learn, to question, or even to accept. It just asks us to go on auto-pilot for the convenience of people who are insecure about their own beliefs and need to bolster their own tottering faith by imposing dogmas on other people.
Because the idea of institutionalizing “In God We Trust” in classrooms turns me off so much, it actually prompts me to feel very un-teacher-like: crabby, uppity, and moralizing rather than open-minded and ready to think. It is unlikely that anyone will ever think of mounting such a plaque in any classroom I teach in–thank God! 
--but I can’t help but feel really badly for the OP’s teacher.