Actually, "itthon" is always "my home", and used only when I am actually home. It literally means "here at home". So, talking about home at work: "otthon". Talking about home while at home: "itthon".
There is nothing creepy about being a professional photographer and having a studio at home.
"Otthon" can be anybody's home, but then you have to make it clear in the context whose home you are talking about. "Otthonuk", on the other hand, is clearly "their home(s)".
Meh, don't read into it that much. It's more vocabulary than anything.
I got burned with "Színésznőket fényképek otthon." because I am not familiar enough with a relatively new verb ....fényképezni.
This photographer must have a studio at his/her house.