I was experiencing the same issue as all of you family sharing owners: You set yourself up as the owner on family sharing, Added your family members, and On a family member's phone, Apple Music was asking the family member to do the 9.99 single plan or the 14.99 family plan, when clearly this family member is set up as a member on your family sharing, why is it asking me this? etc. SOLUTION: On the family member phone, Music app > top left corner click on the head (profile) > sign out on the bottom. Sign that family member back in with THEIR APPLE ID (NOT YOURS!), and after that, the family member should then be able to use Apple Music as a family member on your 14.99 family plan. NOTE: For me, On one family member phone, it asked me if I wanted to enable iCloud Music Library after sign out and sign back in, and on another family member's phone other it just went back to the normal music screen, but the top right had the magnifying glass and was able to search for and play an artist that was not on that family member's phone (pick an artist/song you know the family member does not have and see if you can play it as a test). Hope this helps!