He may well put you on a draw as well when you donk.
Also if you think he is raising his overpairs, why would he not raise AJ also?
Does he never raise AsKs? AQ?

Code:
Board: Js 9s Tc
Dead:  

    equity     win     tie           pots won     pots tied    
Hand 0:     49.811%      48.79%     01.02%              30916           644.50   { JhTh }
Hand 1:     50.189%      49.17%     01.02%              31155           644.50   { 99+, AsKs, AQs-AJs, KQs, AQo-AJo, KQo }