A Paladin 8 is able to use 2nd level spells, allowing him to apply metamagic feats as for example Extend Spell or Enlarge Spell (which raise the spell slot used to one level higher, so the Paladin can improve his 1st level spells using his 2nd level slot).
However, after attaining the ability to conjure spells in 4th level, he only got one feat (on the 6th level).
Many metamagic feats don't have a prerequisite, including Extend Spell or Enlarge Spell. Also, the general rules for metamagic feats did not explicitly forbid a non-spellcaster to get a metamagic feat.
If that character wanted to use more than one metamagic feat, or if he also wanted to create magic items (feats which explicitly require a caster level, so he would need to spend his 6th level feat on this), do the rules allow him to get the metamagic feat before receiving a caster level?
I also found this answer saying that a Cleric can get a metamagic feat at 1st level even if it raises the spell to a level beyond the Cleric capabilities - however this divine spellcaster is already a conjurer at level 1.
So, my question is: Can a character without caster levels learn a metamagic feat?
P.s.: I know the example would hardly generate a good, optimized build, but I'm interested in know if this is possible (for NPC generation, for example). Also the metamagic feats in question are just examples.