So the second Sarissa error that IE9 gives is actually a really annoying one.  When the AJAX response is being processed, it hits this bit:

var idsSpan=req.getElementById("ajax-view-state");
LOG.debug("Hidden JSF state fields: "+idsSpan);
        

And IE9 chokes on the debug.  Apparently it doesn't want to append the element set, or a null, or something to the string ... not entirely sure.  When I first looked at it, I assumed it was misreporting, but after pulling the function apart and trying again, it continued reporting on the same line.  Below is that function with the debug line removed, which seems to remove the second failure as well.  Same as before, just place this somewhere it will be fired after the libraries load, but before the rerender.

Again, while these changes are lightweight - it is stil overriding a core function, test thoroughly, etc.  Also, be careful cutting and pasting ... if any of the debug lines get split it will toss out an error.

A4J.AJAX.processResponse = function (req){A4J.AJAX.TestScriptEvaluation();var options=req.options;var ajaxResponse=req.getResponseHeader('Ajax-Response');var expiredMsg=req.getResponseHeader('Ajax-Expired');if(expiredMsg&&typeof(A4J.AJAX.onExpired)=='function'){
var loc=A4J.AJAX.onExpired
(window.location,expiredMsg);if(loc){window.location=loc;return;}}
if(ajaxResponse!="true"){LOG.warn("No ajax response header ");var loc=req.getResponseHeader("Location");try{if
(ajaxResponse=='redirect'&&loc){window.location=loc;}else if(ajaxResponse=="reload"){window.location.reload(true);}else
{A4J.AJAX.replacePage(req);}}catch(e){LOG.error("Error redirect to new location ");}}else{if(req.getParserStatus()
==Sarissa.PARSED_OK){if(options.onbeforedomupdate||options.queueonbeforedomupdate){var event=req.domEvt;var data=req.getJSON
('_ajax:data');LOG.debug("Call local onbeforedomupdate function before replacing elemements");if(options.onbeforedomupdate)
{options.onbeforedomupdate(req,event,data);}
if(options.queueonbeforedomupdate){options.queueonbeforedomupdate(req,event,data);}}
var idsFromResponse=req.getResponseHeader("Ajax-Update-Ids");var ids;var callback=function(){if(A4J.AJAX.headElementsCounter!=0)
{LOG.debug("Script "+A4J.AJAX.headElementsCounter+" was loaded");--A4J.AJAX.headElementsCounter;}
if(A4J.AJAX.headElementsCounter==0){A4J.AJAX.processResponseAfterUpdateHeadElements(req,ids);}};if(options.affected)
{ids=options.affected;req.appendNewHeadElements(callback);}else if(idsFromResponse&&idsFromResponse!=""){
LOG.debug("Update page by list of rendered areas from response "+idsFromResponse);ids=idsFromResponse.split(",");req.appendNewHeadElements(callback);}else
{LOG.warn("No information in response about elements to replace");req.doFinish();}
var idsSpan=req.getElementById("ajax-view-state");if(idsSpan!=null){var namespace=options.parameters['org.ajax4jsf.portlet.NAMESPACE'];
LOG.debug("Namespace for hidden view-state input fields is "+namespace);var anchor=namespace?window.document.getElementById(namespace):window.document;var inputs=anchor.getElementsByTagName
("input");try{var newinputs=req.getElementsByTagName("input",idsSpan);A4J.AJAX.replaceViewState(inputs,newinputs);}catch(e)
{LOG.warn("No elements 'input' in response");}
try{var newinputs=req.getElementsByTagName("INPUT",idsSpan);A4J.AJAX.replaceViewState(inputs,newinputs);}catch(e){
LOG.warn("No elements 'INPUT' inresponse");}}
for(var li=0;li<A4J.AJAX._listeners.length;li++){var listener=A4J.AJAX._listeners[li];if(listener.onafterajax){var data=req.getJSON
('_ajax:data');listener.onafterajax(req,req.domEvt,data);}}
var focusId=req.getJSON("_A4J.AJAX.focus");if(focusId){LOG.debug("focus must be set to control "+focusId);var focusElement=false;if
(req.form){focusElement=req.form.elements[focusId];}
if(!focusElement){LOG.debug("No control element "+focusId+" in submitted form");focusElement=document.getElementById(focusId);}
if(focusElement){LOG.debug("Set focus to control ");focusElement.focus();if(focusElement.select)focusElement.select();}else
{LOG.warn("Element for set focus not found");}}else{LOG.debug("No focus information in response");}}
else{LOG.error("Error parsing XML");LOG.error("Parse Error: "+req.getParserStatus());}}}