The game has been released officially multiple times under the name "Castlevania: Rondo of Blood." PSP, PS4 and possibly Nintendo eShop. Sadly, I wouldn't hold my breath on any more old Castlevania soundtrack releases, though who knows with the recent retro collections and that mobile game coming out.
EDIT: Actually, I think it may have just been called "original game" in DXC (I'd have to check the game and/or manual/box) but as of Castlevania Requiem at least, it is officially called Rondo of Blood by Konami:
https://www.konami.com/games/castlev...2018_x_son_rob
EDIT 2: Just booted up my PSP and the original game is indeed called "Castlevania Rondo of Blood" in the menu. So it's officially had that title since at least 2007.