I don't think that I have missed this in previous postings:
2D. Look around very fast ?t?r?e. The T comes from Quarto in 5A which looks right but I don't see how: " doctor, for example, with no points to make a book ( quarto?)
Re 5ac
"9" doesn't refer to clue 9 - but to the number 9 (3 x 3) which is an example of something as is 16, 25 etc. Take (compass) points off and add "to".