I haven't read the book, but I would guess "clap hands" is just clapping the baby's hands or clapping your hands to the baby's hands, with or without music.
I think hidey peep is when a child hides behind something or under a blanket, similar to peekaboo, but not using hands to cover eyes (search hidey peep on YouTube for a few examples).
I'd think patacake refers to the rhyme. At 9 months, the baby isn't expected to actually play patacake (my 2 3/4 year old doesn't even do that yet, though we haven't really tried it much...she could probably learn it now, but not when she was just 2). The baby can enjoy hearing the rhyme, watching you do the motions, and having you clap his or hands together, though. The baby can also just clap along to the rhyme without actually doing the right motions while you do the motions yourself.
For row, row, row your boat, have both of you sit on the floor facing each other and then hold both of the baby's hands in your hands, rowing your arms as you sing the song. Another alternative that I loved and my kids love is to lean /the baby backwards and forwards as you do this so s/he goes from laying down to sitting up (you can also lay down when she's sitting up the sit up as you lay her down).