Much of the time it is an issue of how far the bees draw out the honey arc at the top. With 10 frames it is difficult sometime to get the frames out without squishing bees, but with 9 frames it is easier. But with experience 10 frames works ok.
But with 10 frames that is an extra frame for brood, or 2 extra for 2 deeps, and that equates to what...6000 potential extra bees?
I don't scrape too much bridge comb unless it gets overwhelming, so they don't have to re-comb between boxes. Furthermore, they build bridges with their bodies so can get across those gaps if there are any.
If the bees are at 9 frames, it will be somewhat difficult to go back to 10 because of the honey storage comb, in order to do so you will need to cut them all thinner with a knife, not fun if there are bees on there.
So just do what works for you, it works either way.