@sergeantbucky, Probably but idk for sure
You would think so, as what other motivation would he have for his actions if not working for Hydra? He didn't really have a grudge against anyone in particular ("I want you to know, Cap, this ain't personal"), nor did he really have the need for revenge. The falling Hellicarrier was the reason for his crippled state (as it caused the Triskelion to collapse in on itself, crushing him), so there is nothing personal in that regard.
Plus there is also Zemo in this film too, and isn't he affiliated with Hydra? If he is and Crossbones is subordinate to him and/or working with him for the same reasons then yes he still would be a Hydra pawn. I believe it has been confirmed that they will be working together in some way, hasn't it?