I have restored two BC9000s. You just need to be careful when it is opened. I recall some kind of strap that you fix the stay in to stop the top opening too far will easily break because it has perished. The heavy top can now move too far and may break/bend its mountings.
The recap is straightforward.
Some of my B&O: BV3/32, MX7000, MX5500, LX5500, MX4000, BM8000, BM6000, Overture, BL8000, BM6000 Quad, BM4400, BM3400, BG-CDX, BM3000, BM1001, BM1200, BM1600, BM1700, BM1500, BM1400, BM2400, BM2300, BM4500, BM4000, BVM70, BVS45-2, BVS60, BC7700, BM2200, BM1900, BG8002, BM1202, BVPenta, BVP45