Here are the mistakes in each sentence:

1. **It take** → should be **It takes** (correct form of the verb).
2. **never is late for class** → should be **never is late to class** (correct preposition).
3. There is no mistake in this sentence.
4. **as soon as they got home** → should be **as soon as they get home** (correct tense).
5. **before I will go to bed** → should be **before I go to bed** (no "will" needed).
6. **Did he met** → should be **Did he meet** (correct verb form).
7. **theirs children** → should be **their children** (correct possessive form).
8. **will open the fridge as well as he arrives home** → should be **will open the fridge as well as he arrives** (corrected for clarity).
9. There is no mistake in this sentence.

Here are the corrections outlined:

1. takes
2. to
4. get
5. go
6. meet
7. their
8. removes "home" for clarity (or correct structure).