The Planetary Joys answer "Which house is most like each planet?" Let's go through them.
Saturn is a diurnal malefic. The diurnal malefic houses are the 12th & 8th, because they're above the horizon & in aversion to the 1st. The 12th is most diurnal because it's rising while the 8th is setting. So the 12th is a Saturnian house of isolation, suffering, enemies, etc.
Jupiter is a diurnal benefic. The 11th is the most benefic diurnal house because it's above the horizon and rising while in aspect to the 1st. So the 11th is a Jupiterian house of friendship, alliances, gifts, etc.
Mars is a nocturnal malefic. The 6th is the most nocturnal malefic house because it's below the horizon, still setting and in aversion to the 1st. So the 6th house is a place of injuries and accidents, etc.
Venus is a nocturnal benefic. The 5th is the most nocturnal benefic house because it's below the horizon, still setting and in aspect to the 1st. So the 5th house is a place of bow-chicka-wow-wow.
Mercury has no clear diurnal/nocturnal or benefic/malefic status, though it has slight diurnal tendencies. The 1st whole sign house straddles both day and night, but it is slightly more diurnal since it's where night becomes day. So Mercury joys in the 1st.
The Sun is just diurnal, rather than benefic or malefic. We have 2 choices, where the Sun peaks in the 10th or where it changes direction in the 9th. The Sun joys in the 9th because it's the most diurnal, it's as far as the day goes, as diurnal as you can get before sunset.
The Moon is just nocturnal, rather than benefic or malefic. The most nocturnal house would either be the 4th where the Sun rests or the 3rd where it changes direction. The Moon joys in the 3rd because it's the most nocturnal, it's as far as the night goes before sunrise.
This has interesting implications for the outers. If we were able to tell whether Uranus or Neptune were benefic/malefic or diurnal/nocturnal, we could assign them a Joy.
This is completely hypothetical, but Neptune is a planet associated with dreams, visions and sleep, while Uranus is a planet associated with waking up and raising hell. Superficially this would make Uranus diurnal and Neptune nocturnal.
Uranus and Neptune can rarely/never be seen with the naked eye, and the bad houses are known for their invisibility to the Ascendant. If this is the case, then...
Uranus would technically joy in the 8th house, a diurnal house unable to be seen by the Ascendant, and Neptune would joy in the 2nd house, a nocturnal house unseen by the Ascendant.
If you overlaid these theoretical outer planet Joys onto the Thema Mundi, the Aquarius 8th house becomes a Uranian house rather than an Idle Place, and the Leo 2nd becomes a Neptunian house rather than a Gate of Hades.
I don't like how modern astrologers have assigned dignities and such to the outer planets, but I mean, if it was traditionally rooted there could at least be a better argument to make, especially for Uranus & Aquarius with the Thema Mundi & its speculative Joy in the 8th
I have no idea if Pluto is more diurnal/nocturnal, but he definitely seems to be a bit on the bad side. I guess he'd Joy in the 7th, straddling both with nocturnal tendencies, traditionally held as the place of death where the Sun dies, and I guess he is named Pluto after all...
