ZAN Center Controller reported an aircraft deviated off course and flew below the Minimum Vectoring Altitude.

Narrative

Aircraft X was cleared from KTN to ANN via the CETK6 departure; no delay expected; climbing to 060. Upon radar contact and communications with the pilot; I proceeded to provided additional routing to their destination of ZZZ via after ANN direct LVD direct SSR direct ZZZ and a climb to 070. After reading back the clearance direct LVD after ANN; Aircraft X was later observed making a turn direct to LVD; roughly 8 miles prior to ANN; still climbing out of roughly 043 in a 050 MIA (Minimum IFR Altitude) about to enter a 060 MIA. In my initial confusion I asked the pilot to 'confirm direct to ANN?'; I then realized what had happened and issued a Low Altitude Alert and to continue climb to 070 immediately. The pilot safely leveled off at 070 and was deconflicted with inbound traffic with no loss of separation.I believe this situation occurred due to possible pilot confusion and lack of understanding with the clearance of 'after ANN direct LVD' as well as general lack of familiarity with the area and the departure being used. Possibly informing and refreshing the pilot on the importance of remaining on the cleared route for terrain and traffic could help to avoid this situation in the future.