This character is a Other Letter and is mainly used in the Katakana script.
The glyph is not a composition. Its East Asian Width is wide. In bidirectional text it is written from left to right. When changing direction it is not mirrored. This katakana joins with other adjacent katakana to form a word. U+30E9 offers a line break opportunity at its position, except in some numeric contexts.
The Wikipedia has the following information about this codepoint:
Ra (hiragana: ら; katakana: ラ) is one of the Japanese kana, which each represent one mora. Both versions are written with two strokes and have origins in the character 良; both characters represent the sound [ɾa] . The Ainu language uses a small katakana ㇻ to represent a final r sound after an a sound (アㇻ ar). The combination of an R-column kana letter with handakuten ゜- ら゚ in hiragana, and ラ゚ in katakana was introduced to represent [la] in the early 20th century.