The Hollywood Reporter: Can Adults Wear ‘Bluey’ Merch? These Fashion Brands Are Betting on It
From denim shirts and band tees, to cropped blouses and purses, these pieces offer up surprisingly fashionable ways for 'Bluey adults' to rep their favorite show. By Tim Chan If you purchase an ...
Can Adults Wear ‘Bluey’ Merch? These Fashion Brands Are Betting on It
Yahoo News UK: BBC reveals plans to target adults with Bluey ‘lifestyle brand’ for all ages
BBC reveals plans to target adults with Bluey ‘lifestyle brand’ for all ages
"Adult children" comes from "adult children of alcoholics", but now has broader reference to adults who were abused emotionally, physically or sexually in childhood.
Merriam-Webster has an entry for half-orphan, meaning someone with only one living parent. They say specifically a child, which would match the usual usage of "orphan" (as mentioned in the question), but it might be used of an adult sometimes, either jocularly or by extension. This doesn't distinguish which parent is dead, but could be combined with a further explanation if it matters.
The best way to do it, I think, would be to forgo the hyphens completely and go with: I am a psychologist who works with children and adults. Anything else is awkward, ambiguous, or both. If it's necessary to emphasize that this individual works with children and adults (i.e., this isn't just introductory information), you could add in a 'both': I am a psychologist who works with both children ...