OP - speaking as a cat rescuer and someone who has done hundreds (quite literally) of home checks for various organisations that specialise in cats-collies...
The home checker is absolutely not going to give a flying fig if your house is "untidy". They are looking to see you are what you've said you are, e.g. you aren't near a busy road when you've said you live on a quiet rural lane. That you don't have kitten-eating rottweilers who will rip it apart in 5 minutes, when you said you have no dog - that sort of thing. They will want to check that you are not complete morons who know sod all about cats and that you've thought about your decision properly.
If you have under 5's, they will want to see their "natural" behaviour at home - e.g. are they reasonably well behaved and do what they are told most of the time with you being in control, or are they demon hell-children who smear crayon on the walls, boil the pet fish in the kettle, run around screaming, fighting and trying to kill each other all the time and refusing to do anything they are told?
If it was me checking, I'd be looking for somewhere that was safe and quiet for the kitten have "time-out" from the family - it's own basket or bed in a quiet place away from children, where it was going to eat, where you'd put the litter tray, what your garden was like, what arrangements you had to let it in/out, they'll give advice on feeding (My own bug bear is DON'T feed supermarket dried food like Go-cat or Whiskas as it is full of cereals, fillers and artificial additives) and give you the opportunity to ask questions.
An experienced home checker can usually tell what the home is "really" like and whether you are suitable in the first 5 minutes, so don't be shocked if it seems a really short visit. OTOH, don't be shocked if it takes 2 hours either. Especially if you start talking about pets etc. 
Good luck, I'm sure it'll be fine. :)