Found just one male pre-flower, what now?

It says your first grow in a decade ? Did you learn very much a decade ago

Where there is one, there will be more. Either isolate or check often for more and remove them when found. Any seeds produced from hermie pollen will have dominant genes for hermaphroditism too, - and they will not be feminised. No use for anything, unless you are trying to breed a hermie strain!

Its very very rare to just have one, its possible but unlikely its alone- there will be more. If you really cant see any and I mean u checked every single node - and u do this daily and u dont see any, then yeah u can leave it just fine. If ur willing to check that hard and u dont find any then its just a bizarre glitch in the genetics. back in the day i did see a few strains that hermied so lightly u were not even really sure it happened aside from a few dozen seeds per POUND of bud instead of 0 seeds per pound. Ive had a strain myself that only produced nana's on the very bottom of the bud near the node, and just one every 3 or 4 nodes. Another from the same line but crossed with a diff strain hermied so bad it looked like it was trying to stack nanans on top of each other all over the bud even from the tips. So it depends how bad your plant ends up being. Keep the stress low and dont do anything that makes the plants unhappy as that will make the prob worse.

Yes that's a pollen sac. The chsnche of it producing more is 99%. I would isolate it if you dont want your whole crop seeded.

That is a male sac. You have a hermi but it looks like it didn't pop. You can do 1 of 2 things. Cut it down. Or watch it closely and finish. 🤞 no seeds. If you do find some destroy them.

time will tell.. not sure on odds, but it's a risk not worth taking most times. if you can isolate it, then you can safely keep it. be sure never to go from the 'pollen' area to the bloom area... at least not without a shower and change of clothes... just better to make sure you do chores in a way that you hit that pollen area last each day and dont go back into bloom area anytime immediately after... You generally have time before the sacs ripen to find them early on. So, you could give it more time and not risk much. still better to isolate even now, if you can. can always put it back in in 2-3 if you see no other issues arise. tweezing nanners is one thing, but full blown sacs are dangerous... one opens up and could seed entire tent... let alone many sacs opening. with a likely circulation system in there, it spreads out fast, lol..