Could it be an Australian Bush Cherry?

Not if 6 indicates your zone.

Unless it appeared at a garden center there despite not being suitable for year-round outdoor use in the local area - I see tender woody plants in the outdoor plant sections of retailers here every year.

True. I'd assumed it was growing in the ground when photographed.

I purchased it at a plant auction, and they are known for selling tropicals outside of zone 6 hardiness.