I found a workaround even if it doesn't solve the initial issue (related to dependencies of geotools and the deployement into Tomcat)

don't use gt-epsg-hsql which leads your app searching for the EPSG code to decode into the HSQL database.

Rather than using CRS.decode(targetCrs); with

CRS.parseWKT("PROJCS[\"WGS 84 / Plate Carree