there is no bsd port in place at this time.
But you can certainly build a firewall/routing appliance with the pine using usb ethernet.
I will have somethign like that posted on in th elinux tutorials section soon enough
FYI, aarch64 (aka arm64) is now officially supported by FreeBSD, and according to them, most things other than HDMI work. I reckon if you can get FreeBSD to boot and don't mind tinkering pFSense should be plausible, though I don't know how much work it would take.
pfSense can run on pretty lightweight hardware so I'm guessing it is quite capable of handling a home network for most folks.