I want to set up my child’s account (he is 9 yo) and I have no apple device. How can I create this account without familly sharing since I do bot have an apple account

She need to have an Apple ID to set up Family Sharing.

Apple ID - create a new.      

Apple ID – Create        

It can be done using one device, but it is a bit more difficult using only one device. On the device, have her sign into iCloud with her Apple ID and set up Family Sharing. Create the child's ID. Sign out of her ID and sign in with the child's ID. Swap iCloud sign in as required.