Looking at the shop's website, books appear to be the dominant product sold here.  Tagging it as shop=books follows Option 1 for tagging multi-purpose shops (https://wiki.openstreetmap.org/wiki/Key:shop#Multi-purpose_shops).  
For that reason, I'm going ahead and closing this note.  

I don't think it would be wrong to tag it as shop=books;music based on Option 2, if you think that's a better option.  