H.W.
If it were me, I'd think long and hard about this.
Not knowing the child's name probably isn't the issue. If CPS comes to do a health and welfare inspection, other things may come to light.
I'd be stunned if a child was asking me to take them home with them and suggested that there was inappropriate touching going on. In fact, instead of CPS, I might call the police non-emergency line to talk to an officer and get some information about how to proceed.