According to Thesaurus.com, there are many symonyms for whisper including:

breathe, buzz*, confide, gossip, hint, hiss, insinuate, intimate, mumble, murmur, mutter, say softly, say under one's breath, sibilate, sigh, speak confidentially, spread rumor, susurrate, talk into someone's ear, talk low, tell, or tell a secret.

According to SOWPODS (the combination of Scrabble dictionaries used around the world) there are 4 words with the pattern S-S---A--. That is, nine letter words with 1st letter S and 3rd letter S and 7th letter A. In alphabetical order, they are:

sassarara

suscitate

susurrant

susurrate

According to SOWPODS (the combination of Scrabble dictionaries used around the world) there are 3 words with the pattern ----RRAT-. That is, nine letter words with 5th letter R and 6th letter R and 7th letter A and 8th letter T. In alphabetical order, they are:

biserrate

susurrate

underrate

According to SOWPODS (the combination of Scrabble dictionaries used around the world) there are 2 words with the pattern S--U-RA--. That is, nine letter words with 1st letter S and 4th letter U and 6th letter R and 7th letter A. In alphabetical order, they are:

susurrant

susurrate

According to SOWPODS (the combination of Scrabble dictionaries used around the world) there are 1 words with the pattern SU-U---T-. That is, nine letter words with 1st letter S and 2nd letter U and 4th letter U and 8th letter T. In alphabetical order, they are:

susurrate