If Enhanced reflexes is what you want, just get an amulet or belt of dexterity (+2 is common, or +4 for something really good). Way less complicated with less drawbacks, though very pricey. Rule legal too. Since we'll be roleplaying it rather than crunching numbers, it should allow you to get away with being speedy without relying on a unknown or completely homebrewed ability based off a 9th level spell.