She obviously finds him attractive too, or else she wouldn't have changed in front of him so overtly in the first place. She's interested, but she wants a relationship with a grown-up.
Getting changed behind him without warning in the midst of a professional discussion IMO is not the action of an adult (nor even an adolescent, but cultures vary), which is the reason I find it intrusively silly - it's a very bad fit with Carol's personality elsewhere in the film.
It doesn't tell me much about Kirk I didn't already know - he's attracted to women and he likes to look at the person he's talking to, which is a common human trait...
You remember that Carol led Kirk into the shuttlecraft for a reason that Kirk didn't understand, right? "Where are we going?" he asked, or something like that. If it was just a professional conversation, they didn't need to be alone like that. She led him in there in order to
change in front of him, pretty clearly. If she'd wanted privacy, she could have asked him to wait outside for a moment, or changed ahead of time, or afterwards.