That may be true, but Trump said that prior to what has happened since inauguration.
It really is up to Sessions in the long run whether to go after the ObamaClinton crooks. Not Trump.
Just like Sessions decided to recuse himself without telling Trump.
Not really. Administrations have always decided what various departments might emphasize, including the DOJ. Some administrations have set out to go after organized crime, others white collar crime, and Trump and Sessions clearly set goals for the DOJ to enforce immigration law and other laws previous administrations had ignored.
Political decisions have always been made about what the DOJ will or will not focus on.
And Trump decided early on that his administration would not focus on going after the Clintons. If he changed his mind, he should have discussed that with Sessions in private.