At the BA engineering open day they did just over a month ago I pestered the interior team with questions on the -9 so I have a few little nuggets.
The Y class seats are confirmed to be wider. Being able to compare apples to apples with the new WT on the 77W vs. the 787, it's clear that the seats have been designed in different widths for different aircraft. Staff said they received so many complaints about the narrow Dreamliner seats that they've decided to narrow the aisles in favour of more seat width. Personally, I think wide aisles are increasingly important these days as load factors increase and more and more luggage moves up from the hold to the cabin. Additionally, the 78's windows mean that hemmed-in feeling you get with tight configurations is abated a bit, especially for window and middle passengers. It's hard to choose which, but I suppose for the longer routes these -9s will (eventually?!) operate this will be a better config.
The second thing is on the initial no-First config. Judging from the what was said, it seems the number of F seats took a lot longer to firm up than they expected. If this is the case then perhaps the seats indeed won't be ready until the winter schedule. A few staff said they thought they may be going with 12 / 3 rows, but the issue here was with the Club seats behind. Demand aside, 3 rows of First would have only left space for 1 row of club - compared to the exclusive 2 rows in the final config, this would probably have become a cramped single row. The reason being - which is clearly shown in the BA seat map - is that they've decided on a very substantial cabin divider in forward cabin. BA have never had to deal with separating F from Club as F traditionally has had it's own cabin, so the interior guys were saying they'd been looking at lots of different ways to do a proper bulkhead divider rather than a flimsy wall. I would have said this now looks like a wardrobe on the seat map, but as F gets personal ones I'm not sure. So overall I think it could also be that this decision hasn't been made, or that this bespoke furnishing isn't ready, hence the delay for the first cabin.
One last thing, moving the TV to the fixed position apparently means dining for 2 will no longer be an option on the -9. I thought this would be a result of switching to a long slim ottoman as well as not having the guest lean against the screen, but the seats do still intersect so we'll have to wait and see what killed that one.