According to SOWPODS (the combination of Scrabble dictionaries used around the world) there are 11 words with the pattern S--T--I-N. That is, nine letter words with 1st letter S and 4th letter T and 7th letter I and 9th letter N. In alphabetical order, they are:
saltation
sartorian
scutation
sectarian
septarian
septation
siltation
sortation
sortition
subtopian
suctorian