Hi, you can use simple ToD (Time of Day) logic on the script!
Create two different CSQ (CSQ-1 and CSQ-PM), assign agents on the queue based on your preference, assign the CSQ on the script based of time of day setting, you will get the 'time of day' node under General tree at left pannel.
After 9 PM you can just play a message with notification that your agent support is closed after 9PM.
HTH.
Thanks,
Mijanur Rahman