Gambler, it looks like you gambled on this one! The last two digits of the serial # tells the year model (hull bottom, stern area). The most recent year that style of scupper was used was 2009 I believe.
When Hobie put that child perch in the middle of the boat, I think they had someone smaller in mind (as stated in their literature). So the first thing I recommend is to pick another seat when soloing. You can use ballast to bring the boat back on its lines. I use about 55# in the nose (if sitting in the back) or 25# in the stern if siting forward.
Regarding repair, I like 3M Scotchweld DP 8010 or Loctite 3030. They aren't as easy to use as most epoxies, but are the only ones I am aware of that will work on PE on a high stress area. You may be able to access the crack from inside the hull via the nearby hatch. You can smear it on using your fingers using double Latex gloves. Some fiberglass cloth over the repair from the inside may provide additional reinforcement, remembering you have about 3 to 5 minutes max. working time -- everything should be set-up in advance.
Good luck with your repairs and welcome to the forum!
I'll try paddling solo from the rear seat and using ballast as you've suggested. Humm, 
a durable water bag stuffed inside the front hull would make it easy to take on ballast (and dump it) without lugging 50 extra pounds around on dry land.