Practice before the board shall be open to the following persons who have met the standing requirements of chapter 36.70A RCW:

(1) A party or compliance participant to a case before the board may appear personally or by a duly authorized representative. The duly authorized representative need not be an attorney;

(2) Attorneys at law representing a party before the board must be duly qualified and entitled to practice in the courts of the state of Washington or satisfy Washington Court Rule 9 standards.