"How come books like "Kharis: Hellenic Polytheism Explored" and "A Beginner's Guide to Hellenismos" have a different monthly calendar than you do on blogspot? Or not "different", per se, but both those books say that the first day of the month is noumenia, the second is for the agathosdaemon, and so on, but their calendars stop at the ninth day, while your's continue (for example, your's say that the 13th day is Athena's, but the books don't mention that). I'm not saying this very clearly... :/"

No, no, I get what you are trying to ask! You're talking about the 'Mên kata Theion',  the 'sacred month', which goes as follows:

First Decad - Waxing Moon - Mên Histámenos
1. Noumenia - Selene, Apollon Noumenios, Zeus Herkios and Ktesios, Hestia, and the other Theoi of the Household
2. Agathós Daímōn - Agathós Daímōn
3. Tritomênís - Athena
4. Tetrás - Aphrodite, Eros, Herakles, Poseidon, and Apollon
5. The Erinyes, Eris, and Horkos
6. Artemis
7. Apollon
8. Poseidon, Asklēpiós and Theseus
9. General holy day to honour the Theoi; special day to the Muses, Helios, and Rhea

Second Decad - Middle Moon - Mên Mesôn
11. (1.) The Moirae: Klotho, Lakhesis, and Atropos
12. (2.)
13. (3.) Athena
14. (4.)
15. (5.) Dikhomênía - The Erinyes, Eris, and Horkos
16. (6.) Artemis
17. (7.)
18. (8.) Day of purification
19. (9.) Day of purification
20. (10.)

Third Decad - Waning Moon - Mên Phthínôn
21. (-10) Eikás - Apollon
22. (-9)
23. (-8) Athena
24. (-7)
25. (-6) The Erinyes, Eris, and Horkos
26. (-5)
27. (-4) Triseinás - Impure day
28. (-3) Impure day
29. (-2 -- omitted in Hollow month) Impure day
30. Triakás, Hene kai Nea (Hekate's Deipnon) - Hekate and the dead

Many (beginner) books have only the first eight (or nine) days listed. Those are the ones more readily recognised in the Hellenistic community and find their basis in the works of Parker and Mikalson. Mikalson, especially, has found monthly reoccurring religious events on days 1, 2, 3, 4, 6, 7, 8, 16, 18, 19, 27, 28, 29, and 30.The sacred calendar has become a bit of a pet project of mine, however, and I have taken a liking to scouring ancient sources for mentions of sacred days and festivals. The few additionally mentioned sacred days in the Mên kata Theion as well as festivals that very few other reconstructed Hellenic calendars have have been reconstructed from those. I would have to hunt for many of the examples of the theories that I apply but I know Hesiod is involved in at least the fifth days as he says:

"Avoid fifth days: they are unkindly and terrible. On a fifth day, they say, the Erinyes assisted at the birth of Horkos whom Eris bare to trouble the forsworn." -- Hesiod, Works and Days (802-804)