The general "rule of thumb" is that compression ratio needs to be matched to the fuel --- i.e. 9.1:1 for 91 octane, 9.3:1 for 93, etc.
This is for iron heads and a relatively stock cam. Note that these aren't hard and fast limits, just guidelines. It is possible to push them some, sometimes by a lot - but you have to really know what you're doing and also be willing to invest significant time/coin in building the rest of the engine to do it. In the end, unless it's an a dedicated race motor where every last fraction of power counts, the benefit in terms of increased power usually doesn't justify the cost or the risk involved.