How much sugar should i expect to extract from ~9lbs pie pumpkin puree and 4 lbs 6 ro

i added 9 lbs fresh pie pumpkin puree and 4 lbs of 6 row to an extract kit

the extract kit alone has an OG of 1.044, my actual gravity with the pumpkin and 6 row ended up being 1.050/1.051

should i have expected a bigger gravity with what i added or did i have some good efficiency with 6 to 7 added points?

i also overshot the pre boil volume so i ended up with 23.5 liters in the fermenter, there's about .9 liters of trub, so i'm left with about 6 gallons in bottles

When you add something that has fermentable sugars to a beer in addition to the kit you will increase your OG, and both the pumpkin and 6 row are fermentables. It would have been higher if you had either boiled more wort off, or topped off with less water. In my experience you will loose about a gallon of beer with a pumpkin ale when you put the pumpkin into the wort itself, so a 6 gallon batch is a good size.