Good starter crop top

[Cornishwench]

Morning
I need to find a good crop top for my 9yr old daughter for under her school uniform
She’s extremely slim and the standard age 9-11 ones don’t even touch her so ride up when she moves
We are not in a position to go actual shopping in shops yet so I was hoping I could get some recommendations hear! They need too be
Wide cross back sports back
Deep so they cover more ( her preference)
Stay in place
We have tried the Asda sports and TU sports both of which are a bad fit on her
She actually does not need to wear anything yet but would like to start too so I’m helping her with that.
Thankyou

We found the new look trainer bras good for dd who is skinny as a rake!

DD used the M&S ones at that age & stage and found them very comfortable. They were white, so good for under school uniform, and racer back style.

The John Lewis sports style ones come up very small on the ribs, my slim 9yo finds them too tight though I think it’s a question of getting used to it. Uniqlo is also good if you size down. All supermarket ones and Primark just flap and ride up, ime.