The prostration in Sura-Sa`d is not amongst the compulsory prostrations, though I saw the Prophet (ﷺ) prostrating on reciting it.
Sahih al-Bukhari Book 60, Hadith 94
← Previous Hadith I asked Ibn `Abbas, "Should we perform a prostration on reciting Surat-Sa`d?" He recited (the Sura) including: 'And among his progeny, David, Solomon..(up to)...so follow their guidance (6.84-91) And then he said, "Your Prophet is amongst those people who have been ordered to follow them (i.e. the preceding apostles).

Sahih al-Bukhari Book 60, Hadith 93 Next Hadith → The Prophet (ﷺ) said, "A strong demon from the Jinns came to me yesterday suddenly, so as to spoil my prayer, but Allah enabled me to overpower him, and so I caught him and intended to tie him to one of the pillars of the Mosque so that all of you might see him, but I remembered the invocation of my brother Solomon: 'And grant me a kingdom such as shall not belong to any other after me.' (38.35) so I let him go cursed."

Sahih al-Bukhari Book 60, Hadith 95