Pronounce as dāihuǐ, not dàihuì. CC-CEDICT lists it neutral-tone (dai1 hui5), and in speech the 会 is often shortened — usually written 待会儿 with an 'r' suffix in northern Mandarin.
register
Casual spoken word. In writing or formal speech, prefer 一会儿 (yīhuìr) or 稍后 (shāohòu).
