It could be 80. that case goes back that far.
Hmm the 2 sources I checked both said this.
"Start of manufacture for movement 7009 is 1977
End of manufacture for movement 7009 is 1995
The watch was made in March 1980,1990"
http://www.watchsleuth.com/seikodatefinder/?mvmt=7009&case=876a&serial=035588
Yields 90 only. I could go either way on this one.