It means you can't exceed what would be the usual limit of spellcasting - no quickened wish, for example, as that would normally be 9th level + 4 for quicken = level 13 effective, and there is no such thing. The level of the spell plus the metamagic feat modifier can't be over 9 before Spell Perfection negates the additional level requirement from the metamagic feat.
1) Yes, you dont need to have 9th level spell slots to use spell perfection, thats why some 6-level casters take it. You simply make your own "perfect" version of said spell.
2) When a text says "you have the ability to cast" it means you must have it as a spell known or be able to memorize it, items that allow casting it will not meet the requeriments. I believe that recent FAQ's even ruled out spell-like abilities obtained from traits or racial abilities.
With that out of the way, No, because the wand has no requeriment to use it, the spell does, only half-elves can cast paragon surge, due to Range: Personal (half-elf only). UMD would allow you to use a Paragon Surge wand without being one of the classes that can cast it:
alchemist 3, bloodrager 3, cleric 3, magus 4, paladin 4, sorcerer/wizard 3, witch 3
The wand has no requeriment unless the creator choose to make it require a half-elf to use (which would lower the item cost), or enchanted the item (not a wand, but this happens to weapons, armors and wondrous items fairly often) with a special ability that requires a certain class or race.
A forgiving GM could even allow you to emulate a race to obtain a special ability from an item that only works for a certain race/class, like the Belt of Dwarvenkind. Otherwise that specific use of UMD will not see much use.
3) If your character is an half-elf, you wouldnt need UMD at all and the answer would be: Yes, you can change the spell from spell perfection every day, on each cast of Paragon Surge, as long you also know three other metamagical feats.
Best Answer
A " set numerical bonus " is exactly what it says, a set numerical bonus (+1 to save DC, +2 to hit with a ray, etc.). That is what gets doubled. Bonus die from any source are not a set numerical bonus, and do not get doubled. :-(