No, it has to have 'estas' to connect the noun to the adjectives.
I'm not sure, but I think 'La tomato estas ruĝas kaj bongustas" is incorrect, because -s here is for present tense and it stands independent and not as an adjective, as in "Bongustas! Ĉokolado estas bongusta." (Delicious! Chocolate is delicious.)
Can anyone explain why or why not?
The root is
bongust-. The various suffixes include:
-i= verb infinitive
-is= verb past tense
-as= verb present tense
-os= verb future tense
-us= verb conditional mood
-u= verb imperative mood
Making a verb out of a root is not synonymous with "esti [root]-a". Much as in English where, for example, "a hammer" is a noun and "to hammer" means "to use a thing in the same manner one would use a hammer" and not "to be a hammer" or "to have hammer-like qualities". In Esperanto, the verb form of a root means "to perform an action associated with the root".