Impossible to say. It's not simply about being an AU on your dad's CSP.
Any time you apply for any card your entire credit profile is considered and used to determine whether or not you qualify. Accounts where one is an AU are not always considered by scoring models and/or creditors. However, when they are they generally factor in like any other account. The account where you're an AU is not the only thing on your report. If it is considered then the specifics of the account will matter and will have an impact on your credit profile and score. The standard factors for FICO are listed here:
http://www.myfico.com/crediteducation/whatsinyourscore.aspx
tl;dr Being an AU or not being an AU on his CSP doesn't guarantee anything one way or another.
You need to build your own tradelines. If your credit hitsory is new that's already a major red flag. Having new accounts is also a red flag. You really just need to put in the time and responsible usage to build your tradelines and credit profile. As your accounts age and are no longer considered new you'll see less of an impact. With a young and thin credit profile you're going to be very limited in how many new accounts you can add in a given amount of time. You'll want to gradually add accounts to thicken your profile as your profile allows.
Adding yourself as an AU may be beneficial but you need to know the details of his account with regard to the factors above. If the account has 100% postive Payment History, reports with low Revolving Utilization (falls under Amounts Owed), is an aged account (Length of Credit History & New Credit), etc then it may help. If the account has any Payment History issues, tends to report with high Revolving Utilization, is a new account, etc then it won't help you and will harm in cases where it is considered.
