I'm from the Northeastern US and I say them the same. But my sister who is from the same place (naturally) does not say
Carrie the same way that I do. I know this because at one point my niece had a friend named
Carrie and my sister was also friends with
Carrie's mother and so my sister mentioned
Carrie quite a few times. I say both
Carrie and
Kerry so that the first syllable sounds just like the word "care", but my sister said
Carrie so that the vowel sound in the first syllable was like the one in the word "cat". Pretty much so that
Carrie sounded just like the word "carry." Maybe some people pronounce
Carrie like "carry" and
Kerry like "care-ee" or vice versa.