I have not been higher than 73F, like they recommend. This strain kicks out an excellent spiciness and I would not want to cover that with high-temp esters.
You could start a little low, like 62-65, and free rise to low 70's.
I take the "let it free rise" comment to mean don't restrain the temps in any fashion once fermentation has started. I've seen this comment mentioned for several Belgian yeasts, but which ones escape me.