I was looking into just that and apparently Glock approves all SAAMI rated ammunition, including +P (10% above max in 9mm) in their pistols. It wont void your warranty either (unless they suspect you were using handloads).Zero issues putting +P or +P+ loads through Glocks as far as I know. Could be wrong but I have had no issues at all.
147 grain +p loads really bring out the potential of this caliber.
He's trying to get a pistol he already owns to work. A pistol designed for a 41k psi loads when normal 9mm is 35k psi. He isn't just trying to push a normal 9mm to dangerous levels.Get a 38 Super.
41k psi for the 7N21 according to data on Wikipedia. That's above SAAMI +P rated ammo and +P+ is all over the map with various below +P pressure so they aren't a guarantee of anything.
Have you considered handloadng? You could try to find data for 9mm major power level IPSC standards which is above +P. Very few companies (and none available in Canada last I checked) produce this ammo at all so you likely have to handload it.
NATO spec 9mm is said to be around 42k psi based on some reading I've done (not confirmed). Have you tried any of that?