Yes you can park your car at 9:30am. At 9:30 there are no issues driving in...but by 10:15 the car line is usually backed up for a mile! I PMd this vlogger, and he said he was on the ship by 10:30.
If you arrive at 9:59, chances are you will be on the ship within 15 minutes. The real challenge is getting into the port with your car. It's a S*#t show! I would plan to enter the port with your car by 9:15AM...not later than 9:30.
I have 10229 Booked for August. Do all the double Balconies(229) have the 2 lounge chairs? Also, how is privacy? I booked it knowing everyone could see you, but am used to OV balcony. I'm worried that Breakfast on the balcony will be a bust!!LOL