Most wedding use professional photographers or friends or relatives who understand photography.
In the majority the photographer is a paid professional and for that reason assume that they know their stuff. I’ve seen hundreds of photographers at work and they are capable of turning any situation into something beautiful and spectacular. Some ask for certain situations to take photos but generally they prowl the wedding with their cameras shooting the beautiful and the unexpected.
Before a wedding I like to meet the photographer. I advise that I have no problem with them moving around during the ceremony; taking special photos of the couple for instance, the ring ceremony, giving away ceremony, the vows etc. Sometimes the photographer and myself work to orchestrate a photogenic moment or I use my p.a. to announce group photos.
When a family friend is the photographer I usually end up taking group photos. Me, the photographer of last resort.
I suggest giving him/her all the leeway they need to produce images of a wonderful wedding.