WoL from RMM Provider Pulseway and a LAN device ONLY

[Sam of Ham]

Hi all! I know WoL questions have been asked here before, but this one is a little different from those, mostly because I want to set up two methods for WoL; from an RMM tool, and from a LAN device like HomeAssistant.

Firstly, I've seen this https://blog.fuzzymistborn.com/opnsense-wol/ regarding setting up HomeAssistant as a LAN WoL device, and I'm moderately comfortable with it, although I believe HA has more native tooling now for remote startup/shutdown. As far as OPNsense queries go, I'd essentially like to simply ensure HA or another server can send these packets in LAN, without fear of exposure. My guess is the default OPNsense config wouldn't allow WoL or anything else unnusual like this without expressly setting it to, but worth asking if I need to do anything else!

More to the point, I'd also like to have an RMM tool (Pulseway) trigger WoL. It has the functionality built in (https://forum.pulseway.com/topic/14-wake-on-lan-wake-on-wan-over-internet/) and just needs magic packets on port 9 passed through. I'd like OPNsense to safely allow only these packets, on only that port, from only our unique server instance (example.pulseway.com) and that's question #2 - how to properly set that up.

Thanks all in advance for your help and hope ya'll are having a great day, wherever you are!