>>1. Ignore the prefix 9 when the customized phone I have dials upon pickup
The OBi dial plan (digit maps and outbound call route) can modify the digits dialed. The syntax <9:> would match 9 and replace it with :nothing, routing the number dialed without the 9. You would need to integrate this into your dial plan.
Or maybe you can customize your phone to not dial the 9.
>>2. Create a feature in which obi autodials a specified number when the phone is picked up.
Page 199 in the OBi Admin Guide
http://www.obihai.com/docs/OBiDeviceAdminGuide.pdf suggests that <S0:1234> is the syntax for a hotline that dials 1234. I have not tried this.