This shouldnt be a problem. Os3.9 comes with a free copy of gensis. You should be able to set this to use DHCP and just set the gateway IP as the IP of your router. Set the DSN to the router IP too and you will then get internet access.
for shared drives you will have to use SAMBA. Good luck. never got it working though many on here have. Do a search for samba on Amiga.org and you find some good guides and advice.
