Mythology/Percy Jackson tours Athens in Nov

Here is the most prominent, best-reviewed Percy Jackson tour: https://greekmythologytours.com/percy-jackson-tour Finding this took 3 seconds; did you try first.

Delphi tours are trickier -- because there are many 1-day bus tours, and they are ALL nightmares, really. Because it takes 3 to 3.5 hours each way (PLUS sometimes additional time because they pick up passengers at hotels before exitiing city). These busses arrive ALL at the same time -- not as many in the fall, fortunately -- the guide takes u up in the ruins for about 1 hour, then they all invade the museum at the same time, about noon. There, it's so crowded you can't see things well, and the noise level makes it hard to hear the (mediocre) guide explanations. Then - because of the tour's priorities -- you're dragged away from the museum, no time to walk downhill to the beautiful "Tholos" structure that's on every folder. You're taken whether u want it or not, to a mediocre group lunch you didn't sign up for but which you pay for (can you spell "kickback"?) and THEN to a tacky souvenir shop (Kickback again?) Finally the 3.5 hour drive back into Athens' rush hour.
If you are serious about delphi & have deep pockets, consider driving there yourself & getting private guide (here's a link to the best-known one - http://www.delphi-guide.gr/ - if she's not already booked. IF you want to try D-I-Y with audio-guide help, here's a recent forum link where we discussed various options - https://community.ricksteves.com/travel-forum/greece/audio-guide-recommendations-olympia-delphi-athens-acropolis

SOUNION -- Most of the tours are geared toward Sunset -- so at the very time when you want to appreciate the ruin & the view in solitude, you are surrounded by busloads of other tourists elbowing each other to take pix. Maybe in October it wont be so bad. But you could also consider a taxi or bus visit there on a sunny morning, then descend below the ruins to a beach for a nice October picnic!