According to SOWPODS (the combination of Scrabble dictionaries used around the world) there are 9 words with the pattern R---E---T. That is, nine letter words with 1st letter R and 5th letter E and 9th letter T. In alphabetical order, they are:
raggedest
ratherest
recrement
reiterant
represent
ripienist
rottenest
rousement
ruggedest