crusader enchant works in pvp?

The issue isn't with PvP. You are too low. Crusader has a sort wide band of peak efficiencies. Below that prime level range it procs less frequently and at higher levels it procs for lower values. WoWwiki reports that

At low levels (e.g. level 9) Crusader procs very rarely. Its not known at what level the standard proc rate takes effect.

The standard proc rate is only 1ppm, so it wouldn't be uncommon for it to be abscent for long periods during PvP even at the non-redued rate. Still, it is a very nice enchant to be using. The alternatives are Enchant Weapon - Potency,Enchant Weapon - Mongoose, Enchant Weapon - Executioner and Enchant Weapon - Berserking, none of which are useable on low level weapons.