I plan to start sanding and priming, I plan to wash the truck then sand the hood and prime it, do I need to wash the hood again before I prime it?

No. Just blow it off really good and wipe it down with wax and grease remover. Then lightly wipe over the hood with a automotive tack rag. Good luck

I know that the accepted technique is as above but I get much cleaner jobs by washing before painting. Need to blow out any residual moisture but worth it for me.

I am trying to get primer on some real bad places so I sanded and primed the hood and top of fenders today, they were pretty bad, I sanded with a da 80 grit then went over with 120 I will have to go over some of it again I found a few places that I didn't get feathered out good but there are some deep scratches in the hood do I need to sand down to the metal and feather it out or would I be better off to fill with a glaze?

Its easier to use 2-part glaze over the scratches after roughing up the area a little with P120 or 180. If you go down to metal, you have to build it all back up again.