What's wrong with it being a "Bradley 10"? I would take that scale quite seriously, although that shouldn't make a difference one way or the other.
I think Tom is/was more mathematically inclined and logical than I am, so he used a kind of numeric formula for his scale, with supporting parameters (e.g. no holes to be missed) that gave the impression of approaching the "objective". But what I think Tom was trying to quantify/describe was actually a feeling, a subjective experience -- i.e. that of transcendence.
If Friar's Head provides Bart with what is, for him, the golfing equivalent of a transcendent experience, then it is indeed a 10 on the Bradley Scale -- and as valid for him (and who else should it matter to?) as Tom's scale is to him.
To paraphrase the Andy Warhol saying: "In the future, everyone will have his own Doak Scale, for 15 minutes".
Or to imagine a grumpy Tom: "Oh for goodness sakes, get your own damn scale and then you can give whatever the hell you want a "10" and finally stop bothering me about it every time C&C builds another course!. Man, my mom was right: she used to say 'Tommy, I'm not sure this "scale" thing is a good idea', but I didn't listen!"