EVF is an 'Electronic View Finder', employed mostly I believe on Micro-Four-Thirds 'pseudo' SLR's or 'mirrorless'; to give an SLR like peep-hole view finder without a periscope mechanism looking through the lens
I 'think' what you are talking about as your info suggests a D90 SLR and a coolpix compact, is simply a 'back-screen'
And I can empathize with glare on them. It was actually glare on back-screen only compact cameras that made me eventually take the plunge into digital SLR, so I didn't have to suffer it... because I used the SLR periscope view-finder not the back-screen, which when its 'on' on my camera shows the aperture and shutter and ISO 'settings' and other info I probably dont need to know, and or can still see in the optical view-finder I paid that premium to have on a camera!!!
Hence, fitting a back-screen protector to my widgetal camera is mainly to protect the screen from damage, like a teenagers mobile-phone! And I seldom suffer 'glare' because of it, because I'm using the optical viewfinder I paid the extra to have in an SLR, and not holding the thing at arms length like a mobile phone, wobbling around all over!
So suggestions? Try using the optical view-finder that makes an SLR an SLR, perhaps?
If on the compact? Well, my solution, when I encountered such dire glare, was simply to shoot wide, and shoot blind and crop after if needed; or shade screen with my hand, or shift my view-point a little.. or to use a different camera... like the SLR!