Yes, you could connect the M6E to a Pi via a USB to serial adapter but we don’t have any software or libraries for the Pi to make it work. As long as you wrote your own code it should function.
An alternative would be to put the M6E shield on an Arduino and have the Arduino do the processing for you. That way the Arduino could spit out data to the Pi via USB for further processing. You’d probably need to externally power the M6E shield though, it draws a fair amount of current and might brown out the Pi.