Knit up means to pick up stitches, British style, so you'd pick up 18 stitches, starting 9 stitches before it and ending 9 stitches after it.
Cast on 22 is just that--casting on 22 stitches. I don't have this book, so I can't look at the pattern to be clearer as to what part of the bootie it is.
"Trust the pattern!"
Time flies like an arrow, but fruit flies like a banana.
Hop aboard while we follow the cloud-covered van of knitting harmony, man!! Woooo!! --Hedgehog
IngridKH on Ravelry