I haven’t tried, but I’d really suggest to avoid doing on the fly sass compilation
in the server
alltogether. You are not compiling your java classes in the server either 
In at least NetBeans and IntelliJ you can hook the original ruby based compiler to do the compilation right after you change the file, or do the same from command line (
sass watch
or something). I haven’t used this with Spring Boot apps, but I’d guess it should work just fine.
cheers,
matti