Mods will probably flag your post as piracy. Not accusing you of that, but the way its framed looks like it.
You could make a throwaway psn account, I suppose, and disable syscalls to login fairly safely, but not 100%.
Edit: something else you could do, which is more steps, but you could install DBOFW (I think littlebalup made one for 4.91) and then you can login while on OFW and easily reinstall CFW after themes downloaded from store.