Thanks for you reply. I understand it is early days. I currently have a 5i5RYH which will not be able to play X265 HEVC streams, which I am presuming Amazon, Netflix and the like will soon be moving on to for obvious reasons.
So I have a bit of time to consider. I know the 8th generation NUCs will decode these but if the opportunity is there I would really like to have the very latest technology and from my limited knowledge and expertise it appears to me that the difference between an 8th and a 9th generation should make the latter well worth waiting for.