Yes he has. Heard and saw him do it.
Got a link?
President Obama Likes Hillary Clinton, But Won’t Yet Endorse
http://time.com/3819778/barack-obama-hillary-clinton-endorse/
To be clear: President Obama likes Hillary Clinton and thinks she would be an “excellent President,” but he’s not endorsing her yet.
Although Obama personally praised his former Secretary of State during a press conference Saturday, White House spokesman Josh Earnest said Monday that he’s not offering a full-blown endorsement of her nascent presidential campaign just yet.
“The two of them have become friends, but there are other people who are friends of the president who may decide to enter the race,” Earnest said. An endorsement, he said, would likely come from the president after Democratic voters pick a nominee.