Do you know why he had so much time off between some races? he had 4 months between race 2 and 4 3 (not that bad), but then he had a year and a half between races 8 and 9. That might point to an injury or soundness issues, so I would check that out (contact the trainer/owner, did you have a ppe and did the vet find anything, etc)
We were told he was sold and moved and in doing so missed the season.
They said he never had any injuries and he had a ppe with clean xrays of feet ankles hocks and stifles. He's only getting better- learning the basics and going on trail rides. So far so good!
In Excess is not one of my favorite sires to see up close, as Viney mentioned. If you can keep this one sound that is good, but I have seen lots of broken In Excess get.
Maybe your horse has something going for him, in that he does have some promising lines a little further back on his dam-side. Bold Ruler I've come to identify as a very potent sire in that his close get seem to be precocious both in personality and soundness. I love Nodouble - more specifically, I like Noholme - lots of NZ bred TBs by him that are just stunning big bodied and hardy animals. The Hoist The Flag line is known for game eventers, probably mostly thru Tom Rolfe & Pocahontas.
I always wish I saw more Sing Sing in pedigrees. One of the most catty horses I ever had was a Sing Sing grand get. By that time his influence is nominal, but I have noticed other Sing Sing horses who had his type of body and jump. Sing Sing has a fantastic pedigree for sport, including Son-In-Law who was by Bay Ronald, a very influential TB sire in sport disciplines. Unfortunately in your horse's case, you are seeing Sing Sing through In Excess.
Iron Ruler is one I have taken note of as of late, as he has several grandget doing well in eventing.