Wiping butts by themselves

I am just curious if it is still normal to wipe a kids bottom at 9 years old. They will be 9 in November. I have 2 step daughters and they still want their dad to wipe there butt but only him no one else other wise they do it on their own when he’s not around he still bathes them puts their clothes on them and so on. But I feel like they should be doing that themselves at this point. Is that weird ? I never really had a dad so I don’t know if this is normal and please don’t get mad at me for asking. I also walked in the room earlier to her trying to put her butt on his face when she was getting out of the shower.