I don't know where the "124 addresses" comes from (or the "9% available").
You said the mask is 255.255.255.0 so that allows for 254 addresses. The screen shot shows addresses from .8 to .250 so that's a spread of at least 242 right there.
With only 50 devices on the network I wouldn't worry about it.
Of course, if you have more devices, ones that you perhaps don't know abut, then you might worry.
Devices with two network cards (laptops) might use more addresses than you expect. Smartphones, smart watches, tablets etc may be connecting. Someone may have shared your WiFi network key publicly so you have more connections than expected.
Also count your managed switches, routers, firewalls, servers, network connected UPSes, security systems (cameras and door entry controls), thermostats, printers, etc.