Re: Double Babbling
ukwali, 9 months is still very young. The general guidelines for a 1 year old is that they have 3 to 10 words. If you're concerned, you can have his pediatrician check him out and/or have him evaluated by a Speech Language Pathologist (SLP).
If you live in a western country, you can have this eval done for free and if its determined that theres a delay then speech therapy would be provided, also free of charge and at your home (if thats easiest for you)
But really, it sounds like your boy is doing just fine and is well within the guidelines. If you google about "speech milestones", you can get more info about ages and abilities.