While Y8 features several games that are similar to Minecraft, the full version of Minecraft is not available through Y8. Some games on Y8 use the word "Minecraft" in their names, but none of these games are Minecraft, nor are they operated by Mojang, the company that created Minecraft.
Mojang's official website states that the PC version of Minecraft is available at Minecraft.net. Console versions of Minecraft are available through multiple retailers. No retailers or websites are listed as providing the full Minecraft game free of charge and there is no mention of Y8 as an official provider of Minecraft in any form.