my DD (almost 9mo) does 'the face' with new foods quite a lot too. sometimes though i find that she'll quite happily take them the second time she's offered them, sometimes she'll take a bit and then pull a face. It seems to vary from day to day.
Like your ds2 though, she'll eat anything sweet - her tongue practically hangs out of her mouth for yoghurt. I think that's pretty common though from a completely unscientific study amongst my friends with babies of the same age.