Nikon D90 SLR autofocus slow in live mode?

Is this normal for Nikon d90 or is it like this for every camera?

Also I would like to sell it on ebay would i be obliged to mention it's live mode focus is slow or would they be expecting this?

Yes, my D90 is slow to autofocus in liveview. But then, I rarely use it. It is much better to use the viewfinder, and get the added stability.

While I might not mention it, I would never, ever deny it.

Live-view autofocus is slow on every DSLR I have experienced especially early models like the D90. I wouldn't worry about it.

The Nikon D90 is a classic and the first digital SLR to include video.

Most people who use a still camera to shoot video, manually focus their shots, so the fact that live view is slow to auto-focus is not an issue.

If on the other hand you are using the D90 as a glorified P&S camera, holding it at arms length, using the LCD to compose your shots, you need to stop doing that and use the camera as it was intended to be used.

By holding the camera against your face, using both hands, you provide a much sturdier platform and will reduce the chance of getting blurred images caused by camera movement when your nearly two pound camera is being held arm's length. See page 37 of the user manual to see how to hold your camera while looking through the viewfinder.

If you are planning on buying an upgraded Nikon camera, consider keeping the D90 as your backup camera. At this time in its age, the camera is worth more to you as a camera than it is in what you can get for a nearly six year old digital SLR on craigslist or eBay. Craigslist is a better option since your buyer can hold the camera in their hands and test it before they hand over their money and you will save the hassle of packaging and shipping the camera.

This is normal. One of the many reasons why live view is not recommended.

Live view uses the contrast method for focusing which is slower, but more accurate.

View finder uses phase method which is faster but less accurate.

No need to mention since this is well known to experienced shooters.

You are not obligated to mention the deficiencies in the normal operation of the camera because this is how Nikon designed the camera to work.

The autofocus in DSLR liveview is generally slower that the phase detect autofocus sensors used in the standard mode. Some newer models are getting better, but the Nikon D90 is their first live view DSLR. So the sluggish live view autofocus is normal.
Live view isn't useful very often, but it is useful sometimes.To compose this shot with my D90 from a very tall tripod, I would have had to be more than two feet taller than I'm to use the viewfinder instead to the LCD.