Look at the nation's GDP before and after "President Obama's policies." Note, once the stimulus kicked in, the economy immediately started growing.
And in this chart we see private-sector job growth before and after the stimulus. Note, once Obama's Recovery Act kicked in, job growth immediately improved. Also note how severe the job losses were when the president took office.
And here's a chart showing the Dow Jones Industrial Average before and after the stimulus. See that low point in March 2009? That's just before the stimulus kicked in.