What the date does settle
The sun sign is beyond argument here. Gemini began around 21 May and runs to the June solstice, and 9 June sits comfortably inside that span in every year sampled at noon from 1930 to 2035. No time zone or birth hour reaches either edge.
The degree is settled to within about a degree and a half as well. That is enough to place the Sun in the second face of Gemini, the ten to twenty degree band the Chaldean order gives to Mars and the triplicity scheme gives to Venus through Libra.
Element and mode come with the sign as well. Gemini is air and mutable, which is a statement about where the sign sits in the circle and in the season rather than a claim about anyone born under it, and this site marks that distinction rather than blurring it.
The Moon is the first thing to go
The Moon moves about thirteen degrees a day, which means it crosses a sign roughly every two and a half days. On any given date it will therefore be in one of two signs, and which one depends on the hour, sometimes on a matter of minutes.
Because the Moon is read as the fastest and most personal of the traditional placements, this is not a small omission. Two people who share a 9 June birthday can differ more in the Moon than they resemble each other in the Sun.
There is a further wrinkle for anyone working without a time. Because the Moon is fast, even a rough estimate of the hour narrows it usefully, and a birth certificate that records the time to the nearest quarter hour is enough for almost every purpose.
The horizon needs a place as well as a time
The ascendant is the point of the zodiac rising in the east at the moment of birth. The Earth turns once a day, so the whole circle passes the horizon in twenty four hours and the rising sign changes roughly every two hours. All twelve are available on 9 June.
Latitude complicates it further. Signs rise at uneven rates, unevenly enough that at high latitudes some take twice as long to clear the horizon as others. That is why a birthplace, not just a time zone, is needed before the ascendant can be named.
Which leaves the houses
The twelve houses are anchored to the ascendant, so an unknown birth time leaves every planet in the chart without a house. The Sun's degree is known on this date, but whether it sits at the top of the chart or near the bottom is a question the calendar cannot touch.
This is the practical case for using the widget above rather than a printed date range. Give it a year, an hour and a place and it returns the exact solar degree along with the distance to the nearest sign boundary, which on this date will be a comfortable one.
What remains true regardless is the sun sign and the solar degree, which shift by less than a degree across a whole day. That is the part of a 9 June chart that can be stated without any further information, and it is worth separating clearly from the rest.
Questions people ask about this
Is a 9 June birthday definitely Gemini?
Yes. Checked at noon in every year from 1930 to 2035, the Sun on this date was well inside Gemini, with about eleven degrees of the sign still to run.
What can the date alone tell me?
The sun sign, the solar degree to within about a degree and a half, the face of the sign, and the element and mode. Not the Moon, the ascendant or any house placement.
How close is the Moon to being knowable?
It is narrowed to two signs by the date, and the hour decides between them. A birth near the crossing may need the minutes as well.
Why does birthplace matter if the sign is settled?
It does not change the sign here. It changes the ascendant, the houses, and the exact degree, since the local clock determines the moment being computed.
Which decan is 9 June in?
The second, ten to twenty degrees of Gemini. Mars holds it in the Chaldean order, Venus in the triplicity count.
Is the Sun the most important placement?
Tradition treats it as central, but it is also the least individual, since it is shared by everyone born within about a month. The faster placements are what separate one chart from another.