My partner is bringing our new kitten over the border ( from U.S. to Canada), should there be any problems (details inside)

My partner and I found a kitten at her place in Michigan. I live in Canada. The kitten is going to live in Canada with me. Would it be okay if my partner drove over the bridge with the kitten? Would customs give her any grief? She could explain the situation. I’m worried that they’re going to think that she’s bringing her cat over to come and live with me. I mean, I’m sure it’s not common for people to bring cats back and forth over the border. Also, he will be getting his shots/physical exam done here in Canada next Tuesday, so he hasn’t had his shots (as far as we know because he’s a stray).