I have been trying to make a regular expression for my mobile phones but I can't seem to get it to work:

Here are the conditions for my regular expression:

* must start with `09`
* total length is `9`

Here is my regular expression: 

```
[0]{1}[9]{1}[0-9]{7}

```

**Valid** mobile number `091123456`

**Invalid** mobile number `0991234567` || `09912345`