If you had a v0.8 config before and didn’t change it from the GUI in v0.9 you are OK.
The GUI should show what’s going on, and currently it’s a bit lacking there I know. I don’t want to show log messages in the GUI nor get into the whole business of handling log files. How log files should be handled is very system dependent and what you want is likely very different from what someone else wants. Syncthing can produce more log output than likely want though, already, by setting the various STTRACE options. Note that the log messages for that kind of stuff is optimized for the developer though, and likely won’t make much or any sense to a causal user.
This isn’t a use case I have in mind for syncthing. If you have no privacy requirements, there are all kinds of awesome file sharing tools (Dropbox, regular BitTorrent, etc).
This was discussed in another thread a while back, actually.