A person may not be employed as a teacher in the public schools of the state unless that person possesses a valid teacher certificate except that a person who has made application to the department for a teacher certificate, including a preliminary teacher certificate under AS 14.20.015, or renewal of a teacher certificate that has not been acted upon by the department may be employed as a teacher in the public schools of the state until the department has taken action on the application, but in no case may employment without a certificate last longer than three months. A person who has made application for a certificate under this section may teach for an additional 60 days beyond three months without a certificate if the department grants a written extension. An extension may be granted under this section for not more than 60 days to the person solely due to delay in the department's receipt of criminal justice information under AS 12.62 or a national criminal history record check under AS 12.62.400.