Can a Trespa Meteon panel been glued directly to a plywood substrate?

The answer is no. Because a Trespa Meteon panel expands and contracts based on a moisture variation, moisture migrating from the plywood or from the adhesive could be trapped between the surface of the plywood and the backside of the Trespa panel. This moisture will force the backside of the Trespa panel to expand while the front face of the Trespa panel will remain dry and stable. This reaction will reflect as warpage.