Can we degrade solace version from 9.9 to solace version 9.6
Downgrades are not supported.
Any specific reason, why you want to downgrade ?
Wouldn't it be more useful, to upgrade to a newer version like 10.4. ?
If you really need to downgrade, please open a support ticket, describe your setup and ask for advise.
Is 9.6 still even in Support..?
EDIT: yup, for one more month. https://solace.com/support/support-dates-for-release-versions/