The damage to the hull at the forward quarter of the keel (seen in Figure 1) is quite unfortunate. For advice on making repairs, see the article in this forum at the top of the index listings which will lead you to three good reference articles on hull repair:
Advice on Repair of Unibond Hullshttps://continuouswave.com/forum/viewto ... f=6&t=9254I suggest you read all three linked articles to get a better idea of how to make a proper repair.
In all cases, the first step is to let the hull dry out and for any water already behind the gel coat and laminate to be allowed to drip out and evaporate.
Because the area of damage is part of the running surface of the hull, you should take some immediate steps to prevent further ingress of water into the hull laminate and possibly into the foam interior. For example, if you intend to continue use of the boat before making a repair, apply some quality duct tape that has excellent adhesion and is reasonably water resistant to cover the damaged area. If you are not going to use the boat, get it out of the water and let the damaged area dry.
ASIDE
I am very surprised that an authorized Boston Whaler dealer sold this boat "as-is" knowing that the damage would required immediate repair in order to avoid further harm to the hull.
Because the damage is not in a highly visible area, a repair does not need to perfectly cosmetic and undetectable. On that basis you could very likely make a good repair yourself that is not particularly invisible to the eye, but will stop any ingress of water into the hull laminate and foam. My own preference for making a repair like this would be to buy the WEST System K-105 repair kit for about $60, and also to read their pamphlet on repair of fiberglass hulls with epoxy resin.