Alun, VPI will be able to tell you if the ET2 can be mounted on the Scout. Also, they have always been willing to pre-drill their tables for any tonearm. I don't think that has changed.
I have lived with an ET2 on a VPI MkIII for many years and have always obtained excellent results from that combination. It is hard for me to imagine that the JMW9 could give better results, but I've not heard it. At the same time, I have never found the ET2 to be the least finicky. One needs to take some time and care setting it up initially, but I've always found it to be very stable and reliable over time. As always, YMMV.