How Do Imams Know Who is Going to Jannah or Not ?

For Prophets (pbut) there is direct communication with Allah (swt), so they confirm news about companions going to jannah. Now I want to know how do the Imams conclude who among the Shias are going to Jannah or who is a hypocrite? The 12ers believe Hisham bin Al-Hakam, Hisham bin Salim, Yunus bin Abdulrahman, Zurara bin Ayan are going to Jannah. I'm guessing to them the Imams said so. The question is how do the Imams know these people are going to supposedly enter jannah? When it comes to the Prophet (pbuh) and his connection to the companions the 12ers proudly quote this verse:

And among those around you of the bedouins are hypocrites, and [also] from the people of Madinah. They have become accustomed to hypocrisy. You, [O Muhammad], do not know them, [but] We know them. (9:101)

So if a Prophet does not know without wahi, how is an Imam suppose to know who is good or bad ?