No. Behe did not admit to being a Christian. He admitted that he thought the designer was God. The Court inferred that it must be the Judeo Christian God.
Examine the decision's discussion on page 128:
Professor Behe remarkably and unmistakably claims that the plausibility of the argument for ID depends upon the extent to which one belives in the existence of God (P-718 at 705).
The mere fact that Behe believes in the "existence of God" combinded with the contrived consonance of Behe's science with the Discovery institute and other's who see Behe's practice as affirming Christianity is enough to prove establishment. The loose manner of proving Behe's Christian conspiracy is ripe for legal abuse.