Early Retirement & signing on for credits

I am taking early retirement at the end of this month circa 2.5 years before my 65th birthday. I currently have more PRSI contributions than the required 2080 needed for a full state pension at 66. Should I still sign on for credits for the next few years?

Also after 9 weeks post retiring can I apply for Job Seekers Benefit should I decide to make myself available to seek part-time employment?

Definitely sign on for credits up to the end of the calendar year of your 63rd birthday.
This will allow you to qualify for Benefit Payment 65.

You can apply for Jobseekers Benefit immediately after you retire.
When applying don't simply state that you are retired.
Say you ceased employment due to reasons such as stress or the need for a change of career.