Can outdoor receptacle go right over conduit leading to it?
That is where we normally put them and nothing in NEC forbids it.  

Also note that a lot of outdoor boxes will have a hole right in the back middle to support this.

After very gently inserting your pipe through the tight hole in the back of your box, please release a generous amount of caulk around the pipe to keep the water out. 

(Also box must be screwed/secured into wall)

Examples:

If you want to set it in the wall.

If you want to lay it flat on the wall.