How does magic missile work for wizards past 9th? I know the max is 5 missiles but in the description it states :maximum of 5 at 9th level or higher. Does the damage still increase or does it just top out ad 5d4 + 5 ?
Magic Missile doesn't improve after 9th level. You have a maximum of 5 missiles that each do 1d4+1 damage each.
It tops out (reaches the maximum) of 5d4+5 at 9th then stops increasing.
Intensify would add up to a level 14 progression, which would net you two more missiles.
Actually, no it wouldn't. Intensify is useless for Magic Missile.
Intensified Spell increases the damage dice of the spell by 5. Magic Missiles damage die never changes. Its always 1d4+1 per missile. What does change is the number of missile, which Intensified Spell can't change.
Benefit: An intensified spell increases the maximum number of damage dice by 5 levels. You must actually have sufficient caster levels to surpass the maximum in order to benefit from this feat. No other variables of the spell are affected, and spells that inflict damage that is not modified by caster level are not affected by this feat. An intensified spell uses up a spell slot one level higher than the spell's actual level.
Magic Missile and Scorching Ray damage is not modified by caster level - the number of missile and rays are.