Voltage Question (9V vs 18V)

[Spacecommandant]

I'm just wondering about people's experiences with 9V pedals and unwanted clipping.
I've built a voltage-doubled clean boost with an op amp buffer at the beginning of the signal.... sounds really nice.
I'm thinking of removing the doubler and keeping it at 9V but I've yet to try a variety of guitars through it at 9V.
Has anyone experienced unintended (harsh) clipping from particularly hot pickups in 9V pedals (clean boosts) that don't use voltage doubling, and do you think it's a good idea to stick with 18V or do you think 9V is good enough in the majority of scenarios?

Thanks....