Deciding to save the windows or replace them depends on a couple things. Your windows with 9 panes are probably a style which being old is not easily replaced and may well compliment your house's looks. On the other hand, they will not be as tight and being single pane, not as energy efficient. Sometimes aesthetics outweigh efficiency. As for deglazing, it is not too hard. You should pick out all the old hard glazing and then put in new. It is sold in tubes (like caulking) which make installing it easier. Squeeze it in and then use a putty knife to wipe it flat into anise triangular bead.