for 8,000 watt generator there is two diffrent wattage it will read either it will read Surge { maxuim } wattage or contsant watt or rated wattage which that mean the generator can go up to the X numbers of watts before it get overloaded.
However with 8KW { Kilowatts } unit it will handle pretty good amount of load without issue beside few very large motour load { typically A/C unit is a iffy depending on surge rating }
But for common household appalinces that is a brezze however make sure you have proper transfer switch and also want to give you a head up make sure you balance the load this is more noticeable on generator power mode than normal uility power mode.
As far for the well pump motour in most case it will handle up to 3/4 HP without too much issue as long you don't have much load on the generator but when you get full load then you will run into it{ may can trip the generator breaker if overloaded some case it may stall the engine }
Most of resdentail well pump what I heard and see useally half horsepower is the most common one but there are few case 3/4 is pretty common but not on the farm they will go more than a horsepower or larger.
Merci,
Marc