The EASA list of class and type ratings is here:
https://www.easa.europa.eu/sites/def..._List_Acft.pdf
In that list, there is a separate B717 rating, one for the DC-9 10-50 series and one that covers the DC-9 80 series as well as the MD88 and MD99 series. So three different ratings, confirming your suspicion.