It is very unusual for an adult male to show that kind of interest in young underage girls. Most men understand that attention like this coach is showing is going over the line. Consider the other fathers in the group, they are not acting like this man. So he stands out in his behavior. Touching, buying gifts and befriending are all tools pedophiles use to "groom" their victims.
It is also very telling that so many parents are expressing concerns. If all of these adults are noticing, then something is wrong.
Many people who abuse younger children are charming and very easy to get along with. They make themselves that way so it is easier to gain access to children. The adults are caught off guard because the perpetrator was so kind and caring.
Also, this coach is targeting the most vulnerable of children among you- the two girls from a broken family with no caregivers in sight.
There is definitely enough here to be very suspicious and to report this man's behavior. If the volleyball team is through the school, then talk with the school counselor and/or principal. As many parents as possible should report what they have seen and when (keeping track of any out of the ordinary behavior such as gifts, taking girls somewhere alone especially hotel rooms, etc helps. Note the date and time). Also, the local police can be notified. You may not have solid evidence, but getting advice from the police on what to do is helpful. You may also be able to file a report. Ask if your local Children and Youth services should be notified as well.
I hope this helps you,