What would be a good 1 day itinerary 11am-9pm for a first time visiting DC, including eating supper somewhere?
Mint & Washington Monument are probably the best to go early. ( Tickets run out unless you order in advance )
Then any of these
Capital
Air and Space
Whitehouse
Washington Monument hasn't re-opened yet, and while they say August, I wouldn't trust that until they actually open. There is no mint in DC (unless you mean the office headquarters), so you probably mean the Bureau of Engraving. I don't think there's a way to order in advance, so that means potentially spending time waiting on line, with the possibility that they'll run out (they often hand out all tickets for the whole day within hours). Not ideal for a 1 day trip.
Newseum, untill closing time
Walk the national mall
IMO, for a 1 day trip, you stick to the National Mall 'extended'. To me, that means the mall proper (with all it's museums), the Capitol Hill, and all the monuments extending to the Potomac/Tidal Basin area. You can throw the White House in for good measure if you can get the full tour tickets in advance from your congressperson. I'd put the Capitol and White House tours at the top of the list. Then Washington (if it's open) and Lincoln Monuments. Then any Smithsonian that specifically interests you (Air and Space, American History, Natural History are all great, to name a few). The rest of the monuments, which are located between the 2 mentioned above, as well as around the Tidal Basin (which is just south of the others) are only really worthwhile if the weather is nice or if you're specifically into that kind of thing. And you can pop into the Supreme Court and/or Library of Congress if that's of interest, both of which are right across from the Capitol visitors entrance. That's more than enough for a day IMO.