ish is a very informal way of saying approximately or around.
so 9-ish means around 9 o'clock rather than precisely at 9 o'clock. If someone was coming to see me at 9ish I'd expect them sometime between about 8.40 and 9.20.
The suffix -ish means like, almost like, similar to. It is most common with color adjectives: yellowish, whitish, blackish, reddish, grayish, ... It is added to some nouns: womanish, mannish, girlish, boyish, shrewish, oafish, boorish, elfish, impish, foolish, clownish, snobbish, prudish, hellish, devilish, mulish, freakish