Hi,
Happy to help.
The "APIs" used by Spectrum are installed with the product so there should be no additional components required. This excludes CORBA however as you will need to download/install your own CORBA SDK. All of this is nicely documented in the CA Spectrum Integrators Guide:
https://support.ca.com/cadocs/1/CA%20Spectrum%209%202%203-ENU/Bookshelf_Files/PDF/Spectrum_Integrator_ENU.pdf and the Development API Reference Guide:
https://support.ca.com/cadocs/1/CA%20Spectrum%209%202%203-
ENU/Bookshelf_Files/PDF/Spectrum_Development_API_Ref_ENU.pdf
I would strongly recommend using the Spectrum Web Services API over CORBA or CLI based on the fact that the Web Service API uses the RESTful model and supports both XML and JSON data. This is a SOAP-less technology whereby verbs are Create Read Update and Delete (CRUD). You can review the Web Services documentation here:
https://support.ca.com/cadocs/1/CA%20Spectrum%209%202%203-ENU/Bookshelf_Files/PDF/Spectrum_Web_Services_API_Ref_ENU.pdf
As far as certificates, you could use either a self-signed (users will be prompted however when accessing that it is self-signed) or authoritative signed.
I hope this helps! Our documentation in these areas is robust so I would encourage you to review.
Thanks!
Jason