When I first got my Alumacraft V16, I had my trusty 1990 Evinrude 15hp on it. So, that's a motor which only weighs about 75#'s. A four stroke 9.9 will be laughably heavy and under-powered comparatively.
With me, my wife, and two kids, I could only get to 12mph and it wouldnt even come close to planing - it just pushed the boat *through* the water, not on it. That also made the gas mileage on it atrocious.
I upgraded to max hull power (25hp, 2-stroke) and I can plane 4 adults and my two kids, and run at about 20-22mph without a problem at all, in protected, oceanic waters - even better performance on calm, flat lakes. With just the wife and kids, 26-27mph and on plane in a couple of seconds is standard. I can even plane it with my fishing buddy sitting on the bow bench, and he's somewhere in the 350-400# range.
There is no way you are going to get a 325#, 16' boat to plane with a 4 stroke 9.9 unless the boat is completely empty other than you, with a small gas can, and you are under 200#'s, with a massive tail wind - then you *might* have a chance.
I'd also point out that both Alumacraft's 1648's (the Jon and Mod-V) are rated for 35hp! That is 3.5x more than what you have on there now.
Another piece of sage advice I received here was that for a family with kids, 14' is not going to be enough in the long term. They were right. The 14' we had before this lasted about 3 years, and then it was obvious we needed a 16' for comfort. Every time we're out on the water as a family, my wife or I will comment on the 16 being the much, much smarter choice (that's not to say you couldnt with a 14 or even a 12, it just depends on your tolerances and preferences).
I chose the V16 b/c I live in a coastal city, and taking a jon/mod-v onto waters around here would be laughable, or more accurately, downright dangerous. With the V on the ocean, I can cut through 2-3ft rollers w/o problem at speed, and have a very comfortable amount of freeboard. On lakes?... its just glorious.
... oh... one last thing...
If you're out on the water, and you're a LONG way from dock, and you have a child with an emergency, you will NEED to have max hull power available...
... something to think about...