“no gadol assured wearing shorts to kol nidrei.”
I’m not a posek, but a gadol by the name of the Chofets Chaim speaks about wearing shorts during tefilla. See siman tsadi aleph sif kattan heh (and the relevent comments of the mishna berurah). Like the other items discussed in the sif, it depends on the minhag hamakom and what is done when standing in front of “anashim chashuvim”. It may be permitted, it may be prohibited. Draw your own conclusions based on the place you find yourself when it is time to recite Kol Nidre,.