Are the bigger studs meant to be worn everyday or are they for occasions when you want to have extra bling?
If I were you, I would keep the 0.9 ctw as everyday earrings, and get bigger studs for special occasions. Or, you may want to gift the small studs to your daughter in the future. Although I do not know the exact cut spec, I suspect your BN Signature diamonds are very sparkly and bright, and thus they are keepers.
If you agree, then you are free to go to any vendor to get your bigger studs. This time, go as big as you can afford, at least 2ctw, because DSS sets in very quickly and you may find yourself in the same situation as today's. As I said before, to help maximize the stud size, consider going down in color to I, and down in clarity to VS2 (or even eye clean Si1 if the vendors are Brian Gavin or Whiteflash).
If, however, you can keep only one pair, you may at least try selling the smaller pair on your own, before moving to the trade-in option. I suspect there is a good demand for your size Diamond earrings, especially that the color, clarity, and cut grade are top. You never know. It is possible that you may get more than what you paid.