If you like it go under contract. Once that happens an inspection will be ordered..... if the inspection goes poorly (assuming they find real issues) you will then be able to:
1. Renegotiate the sales price to cover the costs of repairing
2. Have the sellers fix it
3. Walk away
Try to bring a "foundation guy" with you to your inspection so that you can get a real idea of costs, etc.
Must be a hell of a first house at 900k. LOL.