What substitution can I make for blonde cane sugar in macaroons?
Sucanat or turbinado sugar (Sugar in the Raw) would be pretty indistinguishable from blond cane sugar. One of them might actually even be the same thing under a different name. 

sucanat

turbinado

Here's a bit more about the subtle differences between sucanat and turbinado. Time article

Here ya go, from Amazon UK evaporated cane juice UK

Also from Amazon UK sucanat UK

And one more turbinado UK