I opine that you should, of course your can use a Christian Cross emblem on your kilt pin. It's an expression of you devotion your faith. Take it from a Rabbi! I have oved 30 kilt pins, polie, military and one with a Star of David, Masonic, and others, and one exclusively for Rabbis.

Good luck to you

Cheers,

Rabbi Dr, Raphael Pazo, Jr.
Rabbi_Pazo