Hi,
I realise no one has really answered your question.
9% means 9% of your DNA matches most strongly with the Ancestry panel from the NE.
This can go wrong for many reasons. It may be that the difference between NE and SE is small, but that is not visible in the summary.
The numbers may be reflecting reality. A lot of Ancestry’s numbers seem to based on assumptions that I’m not sure really hold for the Uk. The reference panel is supposed to be people with deep roots in an area, but 1700 is not really that long ago, and I certainly had ancestors who move large distances and then settled for 200 years or so, so this may produce false groups.
You mention that Davison is a potentially NE name, though you can’t get that far back. However I see you also have Murray in your name list, a good Scots name, if this is in your DNA tree this may also be skewing your results.
Finally it is telling you something about your DNA, perhaps beyond a paper trail and not absolute, but real. I have a similar situation with “Irish” DNA, is this real or simply reflecting the cultural links with SW Scotland where I know I have ancestors. Ancestry have that Data but deem it too complex for us. MyHeritage seems to be leading the way on this front.
https://support.ancestry.co.uk/s/article/AncestryDNA-Reference-Panel