Could somebody please explain

1) what does "9-ish" means when somebody is trying to say time;

2) and what are the effect(s) when you add "-ish" at the end of a word.

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

It is used to form nationality or ethnic group names in a very few cases: Flemish, Danish, Finnish, Spanish, Jewish, Yiddish
It is also a verb suffix related to the Romance language "ir" verbs: furnish, banish, punish, diminish, replenish, brandish, vanish, embellish, ... (Here it does not mean like or similar.)

In many cases it is not a suffix, but part of the root of the word. radish, rubbish, dish, fish, fetish, parish, wish

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Thank you for your comment. I'm Portuguese speaker and at the first time I've read a good and simple definition of ISH.
Students: We have free audio pronunciation exercises.
What does ish mean when used at the end of child?

It would mean "child like".

If you were to say someone was acting "childish" you are saying they are behaving as a child, or immature for their own age.