This character is a Other Symbol and is commonly used, that is, in no specific script. The character is also known as alchemical symbol for gold.
The glyph is not a composition. Its width in East Asian texts is determined by its context. It can be displayed wide or narrow. In bidirectional text it acts as Other Neutral. When changing direction it is not mirrored. If its East Asian Width is “narrow”, U+2609 forms a word with similar characters, which prevents a line break inside it. Otherwise it allows line breaks around it, except in some numeric contexts. The glyph can be confused with one other glyph.
The Wikipedia has the following information about this codepoint:
A solar symbol is a symbol representing the Sun.
Common solar symbols include circles (with or without rays), crosses, and spirals.
In religious iconography, personifications of the Sun or solar attributes are often indicated by means of a halo or a radiate crown.
When the systematic study of comparative mythology first became popular in the 19th century, scholarly opinion tended to over-interpret historical myths and iconography in terms of "solar symbolism".
This was especially the case with Max Müller and his followers beginning in the 1860s in the context of Indo-European studies. Many "solar symbols" claimed in the 19th century, such as the swastika, triskele, Sun cross, etc. have tended to be interpreted more conservatively in scholarship since the later 20th century.