This code
js_obj := oAcroPDDoc.GetJSObject;
js_obj.Collab.showAnnotToolsWhenNoCollab := true;
which used to work in Acrobat 7 and 8 (and was infact required to enabled editing of note/annotations/comments) appears to crash Acrobat 9.
Does anyone know if there is a work around (the one listed here does not work for me). Anyone from Adobe use SO and care to answer?
It looks like you're not the only one with this problem. It has been reported to Adobe as a known bug.