Here's a Calculate Value expression that will do what you want. Rename the Calculate Value output "OptValue"
f(r"%Option%")
def f(opt):
if opt == "YES":
return 1.0
else:
return 2.0
Then, open the Raster Calculator tool and build this expression.
This is the python float function (lower case, not the arcpy.sa tool Float)
"%raster dataset%" * float(%OptValue%)