Don't worry about eating at all about eating.
Just make sure he stays hydrated.
You can offer small worms or rolipolis, but don't
worry if he doesn't eat for awhile. Out of several
babies I've had hatch during the past month, I've only
had one take anything.
Sometimes they won't eat for a couple of months.
If you still have his eggshell, put that in with him.
Sometime they will nibble on their eggshell and the
calcium is good for them.
As far as your other question.....it mainly depends
if you want to spend the time raising a baby turtle.
If he is relesed soon, he has a good chance of being
eaten by something else. You could let him get bigger
and release him. But if you want to release him in the
near future, just find a place with alot of shrubs,
for cover(and awayfrom dogs).
Either way, it hasn't been that long since
his hatchling. I'd let him stabilize for a couple of
weeks at least.