AIA - do I have to use all allowances

Hi

I have a client who has made a profit of £4,500 (first year of trading), he has purchased (had made) a website where he sells services, the website has cost him £9,000.  First of all, can he get capital allowances from the purchase of the website (non tangible asset) however he does take sales through it and if yes, does he have to use all of the AIA (£9,000) i would use all allowances and carry a loss forward to use at first available opportunity but just wanted clarification.

many Thanks

Andrea