It means Allah has given them certain supernatural powers in this universe. We accept that. We learn from Sura Naml verse 40 that having some kinds of knowledge gives you supernatural powers, and the Imams had the full knowledge of the book given to them by the Prophet (s).
However, we don’t have any sahih hadith that calls Imam Ali (a) creator or sustainer. In fact, sahih hadiths reject calling the Imams such labels. Hence, we should not refer to Imam Ali (a) using such titles.