Trying to use points to upgrade for a flight Friday night (I am silver). Told me I was wait listed. There are still like 8 unsold first class seats.....how long does it take for it to clear? Would have thought if I "bought" them with miles I would get it instantly....and the miles were deducted from my account..

Doesn't work that way, unless they have available inventory in the relevant bucket. They don't have to offer a single seat, if they choose not to, and instead sell whatever they can for cash. The only time they should automatically clear your seat is when your flight has that seat in "R" fare class available.

So the booking engine can show F9, implying that 9 or more F seats are available... and all that means is that they're available for sale. The seatmap can show F being wide-open, and that still doesn't mean you'll get a seat using miles. Especially if you're not an elite on UA.

Details regarding fare classes can be found here.

Just because there are seats for sale doesn't mean they are giving away upgrades yet. If there is inventory in the R bucket then your upgrade should clear. If there isn't then you'll have to wait.

When you look at your reservation online do you see a second entry for the flight in question with the notation that it is waitlisted? If not then the agent did it wrong.

What is the route? What is your fare class? Days of week? People could probably opine on the chances. For example if you said "IAH-NRT" or "EWR-NRT" I would say "if you have an L fare you have a chance...if you have a Q fare you're dreaming."

If you're just looking at the seat map and don't know what he meant by F9...
do a new search for tickets on the same route. Click on FARE CLASS on the right of the screen for the ticket that is your flight. You'll see how many tickets are still available in each fare class.
To use miles or an upgrade instrument instantly, you need to see some R fares (or RN if you are elite...can't remember if Silver is high enough to use RN...)

Often they'll release some first class seats to R fare and then process upgrades by miles. This is better for them than just giving it to us cranky 1ks, you're paying something of value. When they do this depends on the route. For example EWR-IAH or EWR-SFO...hahaha. They often won't process any upgrades on these route until day before, and you probably have competition.

You will probably only see the upgrade if everyone else on the plane declines to pay for the upgrade with $$$.