If I take birth control pill every day but the time I take it varies (one time it was within 10hrs), is that still perfect use? Chance of pregnancy?

Once per day. Birth control pills need to be taken once per day. A few hours difference from day to day will not matter. Take one pill per day. If you are not confident using birth control pills consider trying an IUD or Nexplanon. These are the most effective reversible options.