The Blue/Black/Splash gene is not sex linked. Both mother and father have two genes at that location on the DNA. So no, that cross will not get you a sex linked chick.
The B/B/S gene is partially dominant. If both genes at that location are the “blue” gene, you get splash. If one is blue and one is not-blue you get blue. In neither is blue, you get black. But that gene only modified feathers that would normally be black. For a chicken to be solid blue or splash the underlying color has to be solid black. If you have a red chicken with what would normally have a black tail and mix in the B/B/S you will wind up with a red chicken with a Splash or Blue tail.
So if you cross a Buff rooster with a Splash hen you should get blue chicks, whether they are male or female. But Buff sometimes has a funny effect on black. You can sometimes get orange or yellow showing up, either in patches or pretty well scattered about. They will not be sex linked but you can sometimes get some really interesting colors. They will still be mostly black, or in your case blue, but sometimes a lot of yellow or orange shows up when they feather out.
