Is there a way to get the CMOS status?

It could be an RTC (real time clock) battery ... I personally doubt it is a BIOS type battery since Android devices usually write data to NVRAM (EEPROM or flash). There is hardly a specific circuit for monitoring the battery level, let alone that you could read the status: a cheap and easy way to detect a dead CMOS battery on a PC is if the CMOS settings are corrupted on boot (check security bits, checksums, or search obviously impossible settings), thus triggering a warning to the user about a bad checksum or possible bad battery.

It is generally not worth dealing with real estate and partial cost to add a monitor for something of low priority or where software definitions and defaults are acceptable (a server that depends on battery to maintain more critical configuration information in CMOS is to others, and therefore more likely to have such schemas and possibly APIs ... a misconfigured clock on an Android device will be fixed as soon as it talks to the network).

All that said, it's not entirely clear why they bothered to put a battery in this device at all ... but if it's for something more complex than a watch, it's also probably very device-specific and firmware specific (not that easy generalized and accessible from Android directly).