I took my 8 month old kitten to get spade Friday, and I don't know if this is normal or not but where her incision is it looks like there's a little lump under it, her temp is fine she's acting a little different very quiet. Is this normal?

It sounds as if she may have had a suture reaction, lots of times this happens and the result is a small lump. If you are not noticing any discharge and the area has not reopened or red and inflamed she should be fine until morning. That is of course if everything else is normal with her, appetite, attitude, using her litterbox etc. As far as acting "quiet"-is she on pain medication? If so this can have a sedating effect.
Keep in mind I'm only guessing here. If you are worried enough about her it may warrant a call to an after hours clinic.
But I would certainly call your vet tomorrow morning and let them know about it. They may want to look at the incision site just to be safe.
The choice is yours.
And props to you for being responsible and having her spayed.

No pain medication, vet just said to watch her and make sure no discharge is coming from her incision site.

Be sure to call your vet and let them know about this first thing this morning, OK? They make want to give her quick once over just to be on the safe side.

Take care