Can I seal the front of my 2007 TT?

Post a picture, may help with diagnosing, without a photo we are just guessing at it.

Stickers cracking is pretty normal and cannot be helped, it is the nature of the beast, they wear out. Once cracking has started, the only fix is to remove and replace and start the clock over again.

Now if you are talking the surface of the trailer front, it depends on what exactly that front is made from. Some fronts are molded plastic of various types and some are Fiberglass Reinforce Panel (FRP) which would have a "Gelcoat" on the exposed surface.. The Gelcoat can deteriorate/wear down leaving fiberglass and resin exposed..

In the case of Fiberglass with gel coat, best fix is to have it painted with automotive grade paint and be done with it.. Any good autobody shop that has paint dept should be able to take core of it.

Plastic, well cracked surfaces, not a lot can be done there to hide it or fix it.. Might be able to paint it but all of the cracked surfaces will need to be stabilized (bridged), filled in and smoothed out before painting.. Any cracks not stabilized (bridged) structurally will simply crack any paint applied..

Assuming it's the vinyl stickers that are cracked...there really is no repairing them. If they bother you, you can remove and replace them but it's a bigger project than you might think.

If it's actually the fiberglass gel coat, you need to figure out why it's cracking. Getting all powdery can be buffed out but actual cracks would be a bigger issue.