problem with spam handlers not created for mail aliases has been solved in 9.0.1. However, 'mchk' utility was not -- it does not restore spam handlers for mail aliases. I have reported this problem to Parallels Plesk developers.
As for now I have created required handlers for all mail aliases with this command:
ally:/opt/psa/handlers/before-local/recipient# echo "select concat(ma.alias,'@',d.name) from mail mn, mail_aliases ma, domains d where ma.mn_id=mn.id and mn.dom_id=d.id and mn.spamfilter='true' and d.status=0" | mysql -uadmin -p`cat /etc/psa/.psa.shadow` -Ns -Dpsa | while read al ; do [ ! -f $al/*spam* ] && /usr/local/psa/admin/sbin/mailmng --add-handler --handler-name=spam --handler-type=recipient --handler-type-name=$al --executable=/opt/psa/handlers/hooks/spam --context=spam --hook=before-local --priority=10 ; done
Please check and let us know if you have any further questions.