It's a natural phase but you can probably ease it by sitting with her and the stranger prior to letting them hold her. My son had stranger anxiety and seperation anxiety kick in high gear at 6 months. It's still pretty bad at almost 11 months but
it's getting better. Our babies start to realise who their caregivers are and learn that all people are not the same. Some babies don't go through stranger/seperation anxiety roughly but others (like mine) do. Just warn everyone and let them know it takes time for her to warm up to them. Maybe bring a stuffed animal along or blanket and they can have that in arms when holding her.
Here is a good article I found:
What is it?
Separation anxiety and stranger anxiety both coincide with a new intellectual skill called object permanence. They now remember objects and specific people that are not present. They will search for toys that have dropped out of sight. They are able to call up a mental image of what (or who) they are missing. They don’t want the stranger, because the stranger is not you.
They understand about people leaving before they learn about people returning. They can tell from your actions that you are about to leave. Anxiety begins to build even before you leave.
They can’t tell from your actions that you are about to return. They have no idea when – or even if – you will come back. And they miss you intensely. For them, each separation seems endless.
Peek-a-boo and bye-bye are fun ways for us to interact with babies. For babies at this age, these are issues of great concern.