The items below could give you a +9 bonus to disarm attempts. If you have panache points, then it would be +14. On top of your +18, it could be +27 or +32 respectively.
Cloak of Disarming
This cloak is well crafted and stylish. As a swift action, the wearer can direct the cloak to attempt a combat maneuver check to disarm a creature within 5 feet, using the wearer's CMB. This disarm combat maneuver does not provoke attacks of opportunity. If the attempt fails, the wearer doesn't risk losing the cloak. The wearer can spend 1 panache point before making the disarm attempt to gain a +5 competence bonus on the combat maneuver check.
Gauntlets of Skilled Maneuvers
The wearer of these gauntlets gains a +2 bonus on one type of combat maneuver check (such as bull rush, disarm, or steal) chosen by the creator when the item is created.
Amulet of Mighty Fists
This is important for Weapon Special Abilities.
This amulet grants an enhancement bonus of +1 to +5 on attack and damage rolls with unarmed attacks and natural weapons.
Alternatively, this amulet can grant melee weapon special abilities, so long as they can be applied to unarmed attacks. See Table: Melee Weapon Special Abilities for a list of abilities. Special abilities count as additional bonuses for determining the market value of the item, but do not modify attack or damage bonuses. An amulet of mighty fists cannot have a modified bonus (enhancement bonus plus special ability bonus equivalents) higher than +5. An amulet of mighty fists does not need to have a +1 enhancement bonus to grant a melee weapon special ability.
Weapon Special Abilities
This would be important for your Monk levels:
A monk's unarmed strike is treated as both a manufactured weapon and a natural weapon for the purpose of spells and effects that enhance or improve either manufactured weapons or natural weapons.
This special ability can only be placed on melee weapons. A dueling weapon (which must be a weapon that can be used with the Weapon Finesse feat) gives the wielder a +4 enhancement bonus on initiative checks, provided the weapon is drawn and in hand when the Initiative check is made. It provides a +2 bonus on disarm checks and feint checks, a +2 bonus to CMD to resist disarm attempts, and a +2 to the DC to perform a feint against the wielder.
You gain a +1 trait bonus on combat maneuver checks to perform disarm and steal combat maneuvers.