spark plug question

We are finally getting to the good part of the car project and putting together the freshly work motor. It is a 318 with a new compression ratio of 9.5:1. It was down around the 8 or 8.5 range before we started. The question is, what spark plug to use. We were using a Bosch Platinum WR9LP that seemed to work well, but now with the compression change I am guessing we need a cooler plug?