[spoilers] Harry and Ruth. The Wonder Years.

[Byatil]

I think the characters would have known Harry and Ruth had a slightly different relationship just by being around them. Harry and Ruth do have quite a few scenes 'alone' with one another, which is something the other characters would probably have picked up on, along with the way Harry reacted to Ruth's kidnapping in 9.8. It does seem odd for them to suddenly 'realise' the relationship between Harry and Ruth; but perhaps it never seemed appropriate to mention before? The theme of love and relationships is quite a strong one throughout S9, so whilst it is probably just a nice way of slotting the H+R relationship into place, it doesn't seem totally unbelievable that the rest of the team would notice.

It seems to me there has always been a bit of a 'will they/won't they' situation with H+R, and as you say... we don't know what occurs off-screen

I think their feelings for each other are noticeable enough for the other characters to pick up on, but subtle enough for them to realise that it would not be appropriate to mention them. Nevermind the compromising position Harry or Ruth could be left in if news were to spread about their feelings for one another.