Since you said N3DS, I am assuming you aren't looking for the XL version.
My little brother got a non-XL N3DS as a gift from amazon and it is 9.0
Don't know if they'll let you do this, but if you go to Walmart and find one of these game cases (end of post), give them the money, and say that you would like to look at all of the boxes to find a specific model. If they let you, use this link and open it on a phone or something (https://gbatemp.net/threads/n3ds-xl-firmware-by-version-number.381479/) if they do let you, make sure that it's on the list or it might be updated. I am unsure of how likely this will work, but at my Walmart, I saw 2 new 3ds's on 9.5 and another on a version that wasn't on the list, but i didn't have money on me so i wasn't buying anything. You might want to go to a smaller Walmart if you want a higher. And if you end up getting a version number not on the list, return it and post in the linked thread to add a version number.Preferably one on a firmware lower than 9.2? 9.0? A firmware where I can run CFW and or Gateway. Thanks!
Don't know if they'll let you do this, but if you go to Walmart and find one of these game cases (end of post), give them the money, and say that you would like to look at all of the boxes to find a specific model. If they let you, use this link and open it on a phone or something (https://gbatemp.net/threads/n3ds-xl-firmware-by-version-number.381479/) if they do let you, make sure that it's on the list or it might be updated. I am unsure of how likely this will work, but at my Walmart, I saw 2 new 3ds's on 9.5 and another on a version that wasn't on the list, but i didn't have money on me so i wasn't buying anything. You might want to go to a smaller Walmart if you want a higher. And if you end up getting a version number not on the list, return it and post in the linked thread to add a version number.