Inkbird PTH-9C
The Inkbird PTH-9C is a 3-in-1 CO2/temperature/humidity detector with a LCD display. It has a Winsen MH-Z19E sensor which is capable of detecting CO2 between 400 and 10,000 ppm, although the firmware in this device only reports up to 5,000 ppm.
Wireless support?
The PTH-9C does not come with any wireless capabilities, unlike the PTH-9CW model. However, it appears that the main board is identical to the PTH-9CW with some components, including the crucial tuya chip missing.
Is it possible to solder a ESP8266 chip on the existing pads and take readings? Likely not. I don't see any serial traffic on the TX/RX pads, so the firmware that's on the unmarked IC is likely not configured to send traffic out.
If you really do want to get the CO2 sensor data, read it from the MH-Z19E directly from pin 3 (center pin on the 5 pin header) at 9600 baud 8N1. The IC on this unit polls sensor data about every 1 second with the sensor reporting measurements in this format:
start, command = 86, high + low, 42, 3 bytes of 0's, checksum
ff 86 01 f5 42 000000 42
ff 86 01 f5 42 000000 42
ff 86 01 f5 42 000000 42
The important bits are the high+low values, which when read as 0x01F5 gives you 501 (ppm).