Are there other known public security sections other than Section 9? We're all aware of Public Security Section 9, its operatives and scope.

The question is: are there other known sections, and if so, what are their scopes/mandates?
Yes, there are other sections, first mentioned in the first movie.

Section 1
Also known as the Special Service Squad, it acts like a special police unit (compare: SWAT)

Section 2  


  Section 2 is under the control of the Ministry of Health, Labour and Welfare, in charge of conducting law enforcement matters regarding unauthorized experiments and patents take place without the Ministry of Health, Labour and Welfare's consent.


Section 3
Enforces the anti-drug operations in Japan.

Section 4
A special unit in the Japanese Ground Self Defence Forces, also known as "The Rangers".

Section 6  


  Section 6 is an Intelligence, Surveillance and Reconnaissance unit under jurisdiction of the Ministry of Foreign Affairs known as the Treaty Council. 


Qoutes are from the Ghost In The Shell-Wikia.