Unless you're a current CA at 9E, the SSP won't mean much to you. Specially if you're a new hire, since your upgrade would be uncertain at this point due to reduction of fleet.
First officers are eligible for interview, but that's kinda outside of the SSP process, they'll look at you and if you have astronaut qualifications, they'll call you for interview. I think out of almost 1000 FOs, 2 have been called to Interview
Edit: If you apply as off the street, but are currently employed by 9E, they'll tell you to go back to 9E and wait for your turn via SSP. At least that's what they were doing up until January.