The Weekend one reminds me of one we had on Cryptic Stations which was e This was Mile End - though I, like Chalky was put off by the capitalization - and was looking for a "head" or "top" answer.
[MF] I thought Raak had got O - you're saying not ?

Nuts - that "head" was supposed to be hidden.

Crosswords are generally filled in in all upper case, so I think "K" is valid. For "bust down reason", would this be something to do with not wearing a bra? I can't think of a 9-letter way of expressing that though.

Maybe lactating?

Boolbar - you are correct on this one. But the reason I dislike it is because (a) it's ambiguous - the answer could just as easily be bookend; (b) there's no definition, purely a device; and (c) even as a device it's flawed because it's not indicated (e.g. with the phrase "to a setter"). These "inverse clues" are becoming more prevalent, but I don't think they're big or clever.