We are looking to purchase a concert flute for our 9th grade daughter. The band director recommends the Yamaha 500 series flute, but a musician friend recommended the Altus Azumi AZ3000SRBO. Any thoughts?

You should take your daughter to a good flute dealer to experiment as many brands and models as she can, inside the bounderies of your budget, of course.
You can even order a bunch of flutes from fluteworld, for example, so she test play them for a week or so and if she chooses one, return the others and pay for the one.
Who could tell that this or that brand and model is the best for her?
Maybe someone interested in some particular brands, or dealers...
She is the one who can tell it in the first place.
This is not really a "flute" thing. In my opinion this is more like a "headjoint" thing. She will actually choose the headjoint she likes the most.