I would think so? Sasuke and probably Itachi can. Maybe the fact that Kakashi isn't an Uchicha suppresses him from turning it off? anyway, i'm sure Obito can but see's no reason as to turning it off.
Obito is infact able to turn off both his sharigan even though one of them wasent all ways his the reason kakashi cant is because he dosent posses Uchiha Blood thats like Sasuke cant Turn off his MS because he had itachi's eyes implanted U_U atleast i think so