Answer
No — SSL can be configured on an Apps9 application server whether or not the machine is domain-joined, using a very similar overall process to Apps10 (Apps9's installer just presents these options across different screens, making the process feel less streamlined than Apps10's more integrated installer flow). The one requirement that matters regardless of domain membership is that the certificate you install actually matches the URL/hostname your users connect through — a mismatch there is what typically causes certificate errors, not the machine's domain membership status itself.