All true, but Wikipedia is just a reference, not an authority, right? “Wah” and “Wah Wah” are both fine. I assume the “Wha-Wha” spelling you used is autocorrect

All true, but Wikipedia is just a reference, not an authority, right? “Wah” and “Wah Wah” are both fine. I assume the “Wha-Wha” spelling you used is autocorrect or accident? Shopping online it looks to me like “Wah pedal” is more popular than “Wah-Wah pedal”. Here’s a pile of examples of guitarists using “Wah pedal”: https://www.sweetwater.com/c976--Wah_and_Filter_Pedals https://www.sweetwater.com/c976--Wah_and_Filter_Pedals https://www.guitarcenter.com/Wah-Filter-Effects-Pedals.gc https://www.guitarcenter.com/Wah-Filter-Effects-Pedals.gc https://www.guitarworld.com/features/best-wah-pedals https://www.guitarworld.com/features/best-wah-pedals https://www.bestreviews.guide/guitar-wah-pedals https://www.bestreviews.guide/guitar-wah-pedals https://www.musicradar.com/news/the-best-wah-pedals https://www.musicradar.com/news/the-best-wah-pedals