Each registrar of voters immediately after his election shall appoint a deputy registrar of voters to hold office during his pleasure and may, at any time, fill any vacancy in said office. He shall file with the town clerk a certificate of each such appointment and the town clerk shall record the certificate with the records of town meetings. Each deputy registrar of voters shall assist his principal when required, discharge his duties in his absence or inability to act and, in case of the death, removal or resignation of such principal, shall become registrar of voters and appoint a deputy, and shall file with the town clerk a certificate of such appointment, which shall be recorded with the records of town meetings. If a vacancy exists in the office of registrar of voters in consequence of a refusal or failure to accept the office or a failure of the registrar to appoint a deputy registrar, the town committee of the same political party as the registrar of voters who so refused, failed to accept or failed to appoint, or other appointing authority specified in local party rules shall fill such vacancy by the appointment of some suitable person, who shall belong to the same political party as the registrar of voters who so refused, failed to accept or failed to appoint. Each registrar of voters in any town may, as needed, appoint and employ not more than four assistant registrars of voters for each voting district therein, who shall serve at the pleasure of the registrar of voters and assist such registrar in the performance of his duties, and, for purposes of any admission session held pursuant to § 9-19b or subsection (a) of § 9-19c, as many special assistants as are necessary to carry out the duties of such session. Such registrar shall file with the town clerk a certificate of each such appointment, which shall be recorded with the records of the town, and shall appoint such other assistants as are necessary for the performance of duties required by sections 9-12 to 9-45, inclusive, on election day and the six days preceding. Unless otherwise provided by subsection (b) of § 9-19b, in the absence of either registrar of voters, his deputy or any of his assistants, except special assistants, shall have all the powers conferred, and may perform any of the duties imposed, upon such registrar by any of the provisions of the statutes. Each deputy, assistant or special assistant registrar shall be an elector of the municipality in which he is appointed. Each deputy registrar shall also, at the time of his appointment and during the six months immediately preceding his appointment, be an enrolled member of the same party as the registrar who makes such appointment.