For low-latency realtime monitoring when using the native Sphere plug-in one option is to monitor through the plug-in by setting a low buffer size in your DAW. Keep in mind, with some DAWs working at low buffer sizes can be difficult for the DAW to handle without dropouts. Please note that for Avid HDX systems it is necessary to add an AAX DSP plug-in before a native plug-in to engage realtime monitoring through the native plug-in.
Another option is to just monitor the direct analog output of the front capsule, which can be done using any analog or digital monitor mixer. This option typically results in the lowest possible latency, although it is then not possible to hear the microphone modeling while monitoring.
The Sphere microphone hardware has zero latency, just as any analog microphone does. The Sphere plug-in has 0.5 milliseconds of latency beyond the latency incurred by your DAW, which in most use cases is negligible compared to any DAW processing delay.
See the "Monitoring Setups" section in Chapter 4 of the Sphere User Guide for more information on this topic.