In theory, tying MAX17561 HVEN pin to ground, creating an 'always on' scenario should operate normally. The autoretry mode is such that the EN/HVEN pins do not need to be toggled to reset after an overcurrent condition. The overvoltage operation is also such that the IC continues to operate normally once the overvoltage condition has been removed. It would of course mean that the only way to turn off the device completely is to remove the input supply however. As always testing using the MAX17561EVKIT would be recommended before finalizing your design.