If you are a 9th level caster and reduced to casting magic missile, you have bigger issues to deal with. Of course, by that point in the combat, 17 points of damage may make a difference ...
Sure it is not the go to spell at higher levels. And I don't think anyone has said it should be. But it is nice to have in reserve if needed. For a modern RPG analogy, it is the .38 your PC keeps in their pocket for those times when they run out of shotgun shells and the .45 has nothing but empty clips. You don't kick down the door with it in hand, but when everything goes sideways, it's nice to have just in case.
As to the quickened version, sure, it's not something I would prepare for a wizard PC (though as a GM it's oh so much fun to throw it into the mix every once in a while for NPCs to use). That said, there is always the lesser quickened metamagic rod (and I would argue the rods are the way to go rather than the metamagic feats) ... ticket price 35000gp if your GM allows purchase of magic items, 17500gp if the GM allows the construction of magic items (DC 22 spellcraft, DC 27 if the creator does not have the Quicken Spell feat ... by 9th level you should have a spellcraft modifier of no less than 15 and most likely in excess of 20 if you are running with crafting feats).