You should consult the upgrade documentation if you can get to it.
The general answer is "Yes" to both. But, there are particulars.
8.00g73 >> 10.0 or any patch install
(Service Pack 5) 8.0 Service Pack 5 required
9.00.0281 >> 10.0 or any patch install
(Service Pack 2 - KB 923671 - English)
(Service Pack 2 - KB 927368 - Spanish Latin-American)
(Service Pack 2 - KB 929293 - French-Canadian)
(Canadian Payroll Year End - KB 928597)
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Charles Allen, MVP