If your only going to be sticking around the 9-10% area max, I wouldn't think pitching in stages would do much. It's low enough in alcohol that most yeast will chew through all the sugars no problem, and leave nothing for the second round of yeast to work on. Even if you were to pitch the second before fermentation is complete, I would assume the first yeast would easily overpower/out compete the later addition yeast which would impart little to no additional flavor.
However, if you were wanting a specific flavor profile of a specific yeast strain, but were aiming for an abv much higher than its tolerance, that's when you start with the yeast that you want the flavor profile to show through, and after it stops, then pitch a neutral flavored yeast with a high abv tolerance to finish up the fermentation with just that original flavor profile, or one with a complimenting flavor profile to add depth.
With all that being said, you could try pitching multiple yeasts simultaneously at the beginning of your 9-10% ABC cider for something a bit different. Not sure how it would turn out, but people have often asked about doing this on the beer side of the forum with the usual reply that one would always dominate (with how light cider is, I would think though that you may experience different results)