I'm facing a weird behavior on blur with Android 9, the blurAmount is set to 1 and type light, on emulators this works properly, on Android 9 physical device the blur is pixelated.

Did you check, if this issue occur in https://github.com/500px/500px-android-blur ?
Nope, so I created an issue there too as this wraps 500px, to see what happens.
Do you have the property downsampleFactor, in your code? Try removing it or matching its value with blurAmount
@DaniCastel I wasn't using this downsampleFactor, this situation occurs in specific OS Android 9, below that works perfectly.
fixed mine by adding downsampleFactor with low value
Android 9
As I don't have anymore this feature in my project, I can't test it.
Most helpful comment
fixed mine by adding downsampleFactor with low value
Android 9