In La prière d'une vierge, at the beginning and throughout, there are many octaves to be played in quick succession. The problem is, my hands are still growing, so therefore cannot reach to a certain extent. Is there a way around this? If no, does that mean I have to remove the Note 1 or 8 on the octave chord [1 , 8 ]
Just roll the octaves until you hands either grow or stretch enough to play them directly. Twelfths are more problematical; these may still need rolling.
Many beginners (especially those of a young age) face this problem.Unfortunately I don't think there is any way around it.
My suggestion is to practice octaves separately. Try practicing octaves in a scale up and down in order to stretch your fingers. There many exercises of this kind and they will help you play songs that require finger stretching.
Also, take note that some songs might not be that easy to play by young people, when their fingers haven't fully developed yet.
Removing the octaves from the chord's isn't something I would strongly recommend, because the song wouldn't be the same per se. You can try to see what it sounds like without them, but my suggestion would be to practice some exercises for finger stretching.