Is there any way to disable morale like you can in DDSPB?

No there is not because its really tied into things deeper in the college game. Freshmen come in with little relationship and build it up with their new teammates over time, a college coach has much more "power" over players than in the NBA and its also an integral part of transferring decisions where in the NBA a player has a contract and would technically be stuck (of course now they just force trades and the teams always give in but that's a different discussion)