I'll say it is valid to do so.
You can use this as an adjective or a common noun - but you need to be sure whether those who hear you or read this understand what you mean by Cinderella.
If you say "She's a Cinderella", then it means "fairy-tale" ending but I could also say "Cinderella (curfew)" to mean she has to be home by midnight. Another example would be Romeo, it could mean a guy besotted in love but does it also imply a tragic ending?
I can find a valid i.e. dictionary example with the word shylock which is a Shakespearean character and has the derived meaning "A ruthless moneylender; a loan shark" from the character (though it can have unintended negative connotations).
I also see sherlock can be used as a term for private detectives.
Other examples could be calling someone a Barbie(warning: it's trademarked) instead of dumb blonde or a JLo (I'll leave you to work it out)
Of course there are eponyms which is where the name of a person i.e. a proper noun has become the name of a product or place or thing. Words such as atlas, Victorian (era), Alzheimer's (disease) , Atkins (diet), Oedipus (complex) but I don't think that's the usage you're looking for.